# engine won't start when its raining



## cameo89

Thishas happened to me apx. 6-8 times already, when ever it rains kinda hard out my truck will not start, so ill spray cap and wires with wire dryer or electrical cleaner and a shot of starting fluid and it usually starts, it had a complete tune up less than 2 yrs ago, but my thought is that im getting moisture under the cap or something?

Anyone ever have this issue when it's raining out? 
Also it dosent do this when it snows, ONLY when it rains hard.

Thanks, Yon


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## 32vld

What was done for the complete tune up? How many miles since then? What year truck?


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## cameo89

1998 Chevy 1/2 ton 4x4 5.7L 
Probably 16-18k miles since tune up, but its been doing this for some time now.


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## clark lawn

replace your cap and rotor, you have a crack somewere. it doesnt go it when it snows cause the air is cold and all the moisture freezes but when it rains it is getting wet.


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## cameo89

clark lawn;1255703 said:


> replace your cap and rotor, you have a crack somewere. it doesnt go it when it snows cause the air is cold and all the moisture freezes but when it rains it is getting wet.


Thanks
I remember this happened to me many yrs ago, I just wanted to get another opinion before I spend more money. But I have to start somewhere.


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## brad96z28

Definitly dist cap common prob and only get delco.


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## NBI Lawn

brad96z28;1255797 said:


> Definitly dist cap common prob and *only get delco*.


This...


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## cameo89

brad96z28;1255797 said:


> Definitly dist cap common prob and only get delco.


Ok! Not really sure what's on there now because the tune up was done the weekend before I bought the truck. But will replace cap and rotor with Delco products tomorrow and go from there! 
Thanks guys


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## 2COR517

Make sure the vents in the dist base are clear. There are two of them. The original design used screens. If you have screens, pop them out. Later designs used two "half moon" baffles. Just make sure they aren't plugged with debris.


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## purpleranger519

I have 2 of the exact same truck and both had that problem. I did the cap and rotor, plug wires, ect. I found it to be the fuel pressure regulator. Changed it out truck starts fine. Why that causes the hard starting in wet conditions is beyond me and when I ran across this issue on chevyforums I thought it was hard to believe that would fix it. Although, it did.


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## 32vld

Cap rotor and wires should be replaced every 50,000 miles/5years. That is the useful life of those parts.

Useful life means that after that point those parts tend wear enough that the odds are you will have problems from that point out.


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## cameo89

purpleranger519;1255960 said:


> I have 2 of the exact same truck and both had that problem. I did the cap and rotor, plug wires, ect. I found it to be the fuel pressure regulator. Changed it out truck starts fine. Why that causes the hard starting in wet conditions is beyond me and when I ran across this issue on chevyforums I thought it was hard to believe that would fix it. Although, it did.


Yea that is a strang one, im gonna start with cap and rotor and see how that treats me, if not so well then...ill do the fuel regulator, but thanks for your input and knowledge.


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## cameo89

32vld;1256007 said:


> Cap rotor and wires should be replaced every 50,000 miles/5years. That is the useful life of those parts.
> 
> Useful life means that after that point those parts tend wear enough that the odds are you will have problems from that point out.


Ok well I've only used around 30-35% of my cap and wire life.


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## NICHOLS LANDSCA

cameo89;1256022 said:


> Ok well I've only used around 30-35% of my cap and wire life.


That doesn't mean it isn't bad. Make sure you get it on just right it's a tight fit and be nice to the little screws


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## cameo89

I know all about the little screws, I lost one a little while back when I changed the intake gasket and played hell finding a new one!
but im on my way to parts store now to get a new cap and rotor. It has messed up before and after the gasket change so im thinking maybe its bad! Ill post my results later once I get it changed.


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## cameo89

Installed new cap and rotor and it started rite up. Thanks for the help guys!


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## 70monte

I had around 25,000 miles on an Accel cap and rotor set when I had problems with the truck running. It felt like it wasn't running on all cylinders. Pulled the cap and the brass contacts had a lot of corrosion on them. Put in a Delco cap and rotor and it ran great. This was on my 98 K1500 with the 5.7L

Wayne


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## cameo89

I replaced my cap and rotor and now it seems slugish, so I stoped by to show a friend what it was doing and I guess its the plugs are fouled out from so many no starts and all the fuel getting dumped into the cylinders, and I was also told that my truck takes a special spark plug that burns hotter than others and they come with a cost of $6 each, and ontop of that my truck has "autolite" plugs which I don't care for, so monday I get to spend another $50. 

I tell ya what I spent more money on truck repairs and maintaining this season than I think I ever have. Im kinda glad its over.


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## cameo89

Im am so donne with this p.o.s. truck, after a new cap, rotor and now new plugs and $120 later Damn thang caught on fire and still wont start...the reason for the fire was I sprayed the wires with brake clean thinking maybe moisture, but I was told that brake clean wasn't flamable. 

So now I go to bed pi$$ed off and miss out on plowing, and probably our last snow of the season. Uggg


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## elecblu

NICHOLS LANDSCA;1256088 said:


> That doesn't mean it isn't bad. Make sure you get it on just right it's a tight fit and be nice to the little screws


I know I am a little late to help the OP , but maybe someone else can benefit. Some distributors are plastic and you can strip out or break the housing for the cap screws very easy, if you are not careful.


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## cameo89

My distributor is cast aluminum. I did get it started this morning after putting a portable heater in the engine compartment near the cap and it started shortly after.


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## MrPLow2011

Umm not sure how old you are buddy. Or how old your truck is, I only say this because this problem is no longer really common. But back in the day. I own a truck that did the same thing. First off go out and look under your hood at night. You may see a spark jumping. But probably what your real issue is since you have owned 2 year and its a gasser. You have a vapor lock, change your fuel filter and run some dry gas through it. Once you get moisture in air you are getting a lock. Also is the gas cap the correct one on the truck?. You would be suprised how a gas cap can mess up some of the fuel injected trucks. but since you are sluggish and Diesel will tell you. CHANGE THE FUEL FILTER.


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## cameo89

@Mrplow lots of good info, I will change fuel filter tomorrow or next, and I really think I need the dry gas because my tailpipe has been dripping puddles, I assume that's why? Again thanks for all the good info.

My truck is a 98
Im a 76 lol


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## brad96z28

Trt spraying the coil with water and see if u see the spark jump. I have seen that many times also.


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## 2COR517

MrPLow2011;1261154 said:


> Umm not sure how old you are buddy. Or how old your truck is, I only say this because this problem is no longer really common. But back in the day. I own a truck that did the same thing. First off go out and look under your hood at night. You may see a spark jumping. But probably what your real issue is since you have owned 2 year and its a gasser. * You have a vapor lock*, change your fuel filter and run some dry gas through it. Once you get moisture in air you are getting a lock. Also is the gas cap the correct one on the truck?. You would be suprised how a gas cap can mess up some of the fuel injected trucks. but since you are sluggish and Diesel will tell you. CHANGE THE FUEL FILTER.


:laughing::laughing::laughing::laughing:

I think you need to do a little studying....


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## MrPLow2011

2COR517;1261559 said:


> I think you need to do a little studying....


Umm no studying needed at all. I have yet to see a year posted for the truck he talking about. I had an old Dodge that would vapor lock all the time when it rained. Till I replaced the fuel filter and ran dry gas through it. His other issue may be cracks in that gel that covers the ECM and he is getting moisture in there. I only gave my own personal issue on 87 Dodge with a 318 that I could see sparks jumping.

As for water out the tail pipe that has nothing to do with water in gas. Thats your cat conv doing its job. could be just vapor or the combustion of hydrocarbon fuel produces both carbon dioxide AND water vapor as a normal part of the process. All gasoline engines produce water vapor and all water vapor condenses if the exhaust pipe is cool.


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## 2COR517

MrPLow2011;1262456 said:


> Umm no studying needed at all. I have yet to see a year posted for the truck he talking about.....





32vld;1255647 said:


> .. What year truck?





cameo89;1255693 said:


> *1998 Chevy 1/2 ton 4x4 5.7L *....


No vapor lock...


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## cameo89

Well im no expert nor a macanic but I have toyed around with mostly chevys all my life.

Goin this morning to buy a new fuel filter, dry gas and gas cap, total is only $21 and hell if it works then ill be happy if not then I have that much more new stuff and ill continue my quest.

I was told by a local friend that in 98 they had a recall on the distributers, not sure how true this is but its some thing to keep on the list of items to replace.

Im surprised I haven't seen B & B yet


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## jb1390

It is also very common on these trucks to have a leaking fuel pressure regulator (inside upper intake manifold). It will drip gas, causing an extremely rich condition. Pressure changes from rain in the air, and then you get a no start. 

Try this next time it happens. Hold the throttle open (gas pedal slightly depressed), when you try to start it. That should help get it going. 

Did you look at the plugs when they came out? A leaking fuel pressure regulator will often clean the rear spark plugs because of the gas dripping into the cylinders. If the front ones looked dirtier than your back ones, then there you go. 

Water dripping out of your tailpipe is because, when fuel is burned, it created primarily carbon dioxide and water. The water condenses, and drips out your tailpipe. Nothing is wrong.


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## cameo89

All spark plugs appeared to look the same, wet and reeked of gas, but after turning the key over a few dozen times and the engine not starting will cause them to foul out, correct?
truck don't seem to run rich.

I replaced the fuel filter(looked as if it was never changed before) poured in some gas dry, a bottle of lucid and installed a new gas cap, I was out the door for $25

Looks like rain in the forcast for tonight so ill see how she does tomorrow morning.


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## MrPLow2011

2COR517;1262465 said:


> No vapor lock...


Ok sorry I didnt you know your were the plow site troll. I will ignore you from now. Thanks for your imput


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## purpleranger519

I'll say it again....it's the fuel pressure regulator. I've had 2 identical trucks do the same thing and thats what was wrong with both.


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## jb1390

You can easily check the pressure regulator using a fuel pressure gage. It should hold steady pressure even when the truck is shut off. You can also check by removing the upper intake manifold and checking for a cleaned area under the regulator, which will happen as they drip.


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## Motorman 007

2COR517;1261559 said:


> :laughing::laughing::laughing::laughing:
> 
> I think you need to do a little studying....


Awesome 2COR!!!!!


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## 2COR517

MrPLow2011;1263167 said:


> Ok sorry I didnt you know your were the plow site troll.


Not trolling. You offered "advice" that was simply and completely inaccurate. Just trying to help the guy stay on track to get his truck running properly.



MrPLow2011;1263167 said:


> I will ignore you from now.


That's fine, there's a whole list of guys that do that.



MrPLow2011;1263167 said:


> Thanks for your imput


You're welcome for the input:salute:


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## 2COR517

purpleranger519;1263210 said:


> I'll say it again....it's the fuel pressure regulator. I've had 2 identical trucks do the same thing and thats what was wrong with both.


The fuel pressure regulator can be problematic on these trucks. But I don't think it would only be a problem on rainy days.


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## cameo89

Ok so we have had a few wet rainy days and it has started every time but its still sluggish or chugging down the road at 55mph and in overdroad, but if I pull it down to 3rd/drive rpms go up and seems to run perfectly.


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## MrPLow2011

2COR517;1264083 said:


> Not trolling. You offered "advice" that was simply and completely inaccurate. Just trying to help the guy stay on track to get his truck running properly.
> 
> That's fine, there's a whole list of guys that do that.
> 
> You're welcome for the input:salute:


Hmm he replaced the fuel filter and it started every time now that its raining. Hmmm and your just trying to help keep him on track to keep his truck running properly. Maybe you should chime in about wet wires and bad cap. All of those were perfect responses to check first. But after that you go to fuel. Now feel free to bash my next post since I really didnt study before I posted it.

Oh and proper maitnence of a motor is never bad advice.


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## MrPLow2011

cameo89;1264187 said:


> Ok so we have had a few wet rainy days and it has started every time but its still sluggish or chugging down the road at 55mph and in overdroad, but if I pull it down to 3rd/drive rpms go up and seems to run perfectly.


Have you checked the frame rails for any rotted fuel lines. fuel air mixture can be a problem. Follow the fuel line along the frame to the motor and look for wet spots. Now I am not to sure where your fuel pump is. And I am sure some one else could answer this. Make sure you buy the proper the fuel line. If fuel pump is in tank its not really a issue. But if its at motor there could be a suction problem that would colapse the hose (I could be way off on this. I know my Diesel had to be the good hose. like 5 a foot) I highly doubt it wil be an issue since you fuel pressure isnt as a high as the new diesels.


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## cameo89

Fuel pump is in the tank and I chased the lines when I changed filter to check for rot or a major bend or twist, im not perfect I have ran stuff over before and maybe I collapsed a line, I am gonna warranty out my new cap and rotor just to be sure before I spend to much more money. I did buy lifetime on them.

Thanks to EVERYONE for your help.


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## MrPLow2011

I know this isnt you problem. But what shape is your air filter in?


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## cameo89

MrPLow2011;1264465 said:


> I know this isnt you problem. But what shape is your air filter in?


I have pulled it out and blew it out with the air gun, it was replaced about 20 months ago or 18k miles, filter window is still green.


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## sechracer

If I remember correctly, your truck needs 65psi to start and 55 psi in fuel to run. If it drops below that, the truck will not start or will stall..... With the rough running, does it get better or worse as the truck warms up? Is your SES light on?

If it runs ok in every gear but overdrive, I would try to run a good dose of cleaner through it.


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## cameo89

sechracer;1264748 said:


> If I remember correctly, your truck needs 65psi to start and 55 psi in fuel to run. If it drops below that, the truck will not start or will stall..... With the rough running, does it get better or worse as the truck warms up? Is your SES light on?
> 
> If it runs ok in every gear but overdrive, I would try to run a good dose of cleaner through it.


Is there a way to check for fuel pressure?

I have ran a bottle of dry gas and a bottle of lucus.
Gonna fill up at a different gas station tomorrow, just to see how that works.(maybe run 93 oct) I normally run 87


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## sechracer

cameo89;1264772 said:


> Is there a way to check for fuel pressure?
> 
> I have ran a bottle of dry gas and a bottle of lucus.
> Gonna fill up at a different gas station tomorrow, just to see how that works.(maybe run 93 oct) I normally run 87


Yes, on top of the motor, by the throttle body, there should be a schrade valve. will look like a tire valve stem but bigger, you can hook a fuel guage up to it. I doubt thats the problem being that it starts and runs. I would pesonally do a heavy dose of sea foam in your gas. 2 cans since 1 will treat 10 - 20 gallons. I do this once a year to my 97.

Does the truck get up to speed fine? just doesnt like cruising in od? like I asked before, does it get better or worse as the truck warms up or does it stay the same?


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## Woodenshoe

Go out at night, somewhere as dark as possible, and check your ignition electrical while the engine is running. Look and listen for arcing (sparks) by your plugs, wires, cap and *ignition coil* (my first guess for your vehicle).


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## sechracer

cameo89;1264187 said:


> Ok so we have had a few wet rainy days and it has started every time but its still sluggish or chugging down the road at 55mph and in overdroad, but if I pull it down to 3rd/drive rpms go up and seems to run perfectly.


The statement you made here makes me believe that its no longer a spark issue or fuel related fully..... With your truck, a mis fire from a bad plug wire will flash your ses light, also, a bad egr or IAC will also throw a code.


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## jb1390

Low fuel pressure because of a bad regulator will not throw a code. Looks like a fuel pressure test is in order. Check with a gauge while driving down the road if possible. Post back with results, and we will go from there.


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## 70monte

Woodenshoe;1264991 said:


> Go out at night, somewhere as dark as possible, and check your ignition electrical while the engine is running. Look and listen for arcing (sparks) by your plugs, wires, cap and *ignition coil* (my first guess for your vehicle).


This is the issue I used to have all of the time on my 98 5.7L and I was using all Delco replacement parts. Check to see if your coil has white burn marks on its body next to the bracket that goes around the coil body. Mine used to arc from the coil body to the bracket and my plug wires would light up like lightning strikes.

My symptons were like yours in that my truck would be real sluggish and felt like it had no power. I would have to replace all of my ignition components except the ignition control module before the power would come back. I talked to a guy that seemed to be pretty knowledgable about the ignition systems on these trucks and he said that once you get arcing anywhere, it starts to break down the rest of the ignition components. The ignition systems on these trucks are pretty hot.

I finally gave up and just drove the truck but since I replaced the Delco plug wires with Magnacor wires, I don't seem to have anymore problems. To be honest I haven't looked for the light show under the hood for quite a while because the truck is still running good.

Good luck.

Wayne


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## cameo89

Well wayne its still not running correctly and I personally think its a ingnition issue, im gonna go check for a light show maybe tonight.


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## cameo89

Just let in run for 10 mins in complete darkness and I could not see any spark at all. Good thing or bad? Probably gonna warranty the cap and rotor and replace the plug wires, and check a price for a new coil.

I just replace the plugs with AC Delco rapid fires @ $5 each so I think im good there.


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## jb1390

Have you performed a fuel pressure test while driving? 

If you have not, you can continue to throw money at it...but that is exactly what you are doing. Throwing money at it based on someones hunch. You need to do some actual diagnostics otherwise you are wasting your money. 

Your hunch that it is ignition is based on no facts. Fuel pressure is an easy thing to test, and it rules out a lot of stuff. I also don't think its ethical to return parts under warranty that you have no reason to believe are faulty.


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## cameo89

No fuel pressure test yet, I still need to find someone with that tester, and still not sure how to drive 55 while looking at a guage under my hood...I guess if it comes down to it Ill remove the hood.

anyways the guy I bought my parts from is a really good friend and he is the one that said he would warranty out my new parts....I'm sure I'm not the only one that has bought new or faulty new parts before! 

Had some ses test done this morning and here are the codes

P0420-catalyst efficiency low-bank 1
P0430-catalyst efficiency low-bank 2
P0304-cylinder misfire detected-cylinder # 4
P0122-(throttle position) sensor

I looked it over good to and noticed that I had a broken vacuum line so I fixed/replaced and its to early to tell but the missing at idol has stopped, gonna go take it up to speed here in a bit to see how it does @ 55+

I also broke the clip that holds the breather on the throttle body, so that will need to be replaced so I'm not getting excess air in the throttle body.


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## jb1390

When you do the fuel pressure test, you can run the hose from the tester up so it sticks out by your windshield wiper, so you can see it safely from inside the cab while you are driving. 

Another test you will want to run - given the age, your catalytic converters could be getting plugged up, and misfires, poor spark plugs, etc will contribute to converter degradation. 

To test the converters-run a vacuum gauge, again above the vent intake so you can see it while driving. You should have a decent vacuum reading at partial throttle. If you do not, it is likely that your converters are plugged. It happened on my truck because of a leaky exhaust valve causing misfires, and by the time I fixed it, the converters were cooked. 

Many reputable parts stores will rent testers (gauges) and other diagnostic equipment for reasonable rates. You could check there for a tester. You could also buy a generic pressure gauge, take the center out of the schrader valve on the fuel line (tire tool works), and get the correct fittings and a piece of hose to run to the gauge. 65 psi should be what you see maximum.


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## Sal_Moides

Have you heard any ticks or ticking, especially when you had the bad idle? Also, while oil and water don't mix, a bit of water/vapor wont stop the gas from burning in the cylinder(like a crazy foggy morning). But, it will conduct electricity, add salt and conductivity goes way up. I'd start with the shorty wire from the coil to the distributor. The electrical potential here is very high and can pass strait through the rubber booted wire and then arc to the bracket of the coil because this is the "path of least resistance". If no help, then, I'd replace the rest of the plug wires and plugs. The other possible problems mentioned here will come at a greater expense. This fix is not going to hurt as much as dropping a fuel tank or pulling an intake manifold. I almost spent $650 to get a sending unit I was told was the problem causing part. Turned out to be an $20 wire. I didn't know you could hear the unit running, learned it here. DISCLOSURE..95 k1500 5.7 ie...that's how I fixed mine it could work for you and its cheap and easy. Good luck chasing it down.


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## cameo89

Ok so I just installed a new set of plug wires and replaced plug #4 (the one that was misfiring) and I've drove apx. 30 miles and NO issues as of yet, gonna wait till it rains again before I start jumping for joy!

Either way I just wanted to say Thank you to everyone who gave input to help me fix my truck.


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## cameo89

Just got home from a 210 mile trip in the rain and truck is still running beautifully.


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## elecblu

Thanks for the follow-up. It's always nice to know what worked and what didn't.


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## cameo89

Plug wires is what fixed the misfire and I believe installing new cap fixed not starting when raining. It seemed to have alot better fuel mileage.


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## 62durango

2COR517 said:


> Make sure the vents in the dist base are clear. There are two of them. The original design used screens. If you have screens, pop them out. Later designs used two "half moon" baffles. Just make sure they aren't plugged with debris.


I know this post is super old but I think your answer is right on. The debris in the screens is the cause of the condensation and judging by the number of sites I've visited there are so many people who don't know it and are spending boatloads of money on caps, wires, etc. It was a guy from a local parts store that told me about the screen thing on my '94 GMC Suburban (he said screen not screens). He said he uses a toothbrush to clean out leaves/dirt - didn't sound like he popped the screen out though. I haven't been able to fix mine - instead I dry out the ignition wire boot or leave the truck for hours/days to dry. Treating the symptom instead of the cause. Reason being I can't find the screens. It's a tough spot and I've tried many times. Can you give me any tips and/or diagram where they are and how to get to them?


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