# 2006 2500HD CEL on for "Random Misfire"



## MikeRi24 (Dec 21, 2007)

I just bought a 2006 2500HD 6.0 with 36,000 miles. 2 days after I picked it up, the CEL comes on steady for like a day and a half. Had is scanned at Advanced, and they said it was a "Random Misfire." Kinda strange, because the truck runs flawlessly. I would have noticed a misfire for sure. Next day, the light goes off, but later as I am driving on the thruway, it starts flashing. I take it back to the dealer first thing monday morning. they kept it all day monday, and all day tuesday. Replaced all the plugs, wires and coils. Here I am today (wednesday), 4 lawns into my mowing route, and the light starts blinking again. I am obviously not happy so I call the dealer right away. They said drop whatever I was towing where it was and leave it (yeah right) and carefully drive it in.. So I drive it home, dropped my trailer and equipment off there, and took it back in. Same code, "Random Misfire" but once again the truck is purring like a kitten. So I had to leave it, and they said they would need it all day today, tomorrow and maybe Friday. This is really annoying because I have gotten NO work done this week, and it looks like I'm not going to either. This was the whole reason I bought a newer truck was to avoid problems and breakdowns and here we go already. Has anyone had this "random misfire" thing? and if so what was the cause of the problem? obviously just throwing parts at it is not the answer, and I need to get my truck back soon.


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## RBRONKEMA GHTFD (Dec 17, 2006)

Will the dealer gove you a loaner truck so you can continue business?


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## Polarisrider (Sep 4, 2009)

I think I have the same problem. When I was driving my truck home from buffalo, the check engine light kept flashing evey 10min or so. So my guy read the same code and said it was random misfire. So I haven't seen it for a while, then tonight while towing my mowing trailer home I got the same thing. It flashed a couple times and then went away, then flashed a couple more times, I never had it stay on steady like you said yours did tho.


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## MikeRi24 (Dec 21, 2007)

RBRONKEMA GHTFD;1092852 said:


> Will the dealer gove you a loaner truck so you can continue business?


No they said the insurance would not allow it for what I would be doing with it.



Polarisrider;1092854 said:


> I think I have the same problem. When I was driving my truck home from buffalo, the check engine light kept flashing evey 10min or so. So my guy read the same code and said it was random misfire. So I haven't seen it for a while, then tonight while towing my mowing trailer home I got the same thing. It flashed a couple times and then went away, then flashed a couple more times, I never had it stay on steady like you said yours did tho.


I noticed that today mine came on while it was towing my trailer in Tow Haul mode, if that means anything.


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## brad96z28 (Aug 21, 2005)

Ckp re learn almost alwyas cures multiple misfires that u can not feel driving. After cking the basics first . I hope u getter a more experienced tech at the dealer this time, Sounds like u got stuck with the oil change boy. Got to love throwing parts at something as simple as this.


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## MikeRi24 (Dec 21, 2007)

brad96z28;1092904 said:


> Ckp re learn almost alwyas cures multiple misfires that u can not feel driving. After cking the basics first . I hope u getter a more experienced tech at the dealer this time, Sounds like u got stuck with the oil change boy. Got to love throwing parts at something as simple as this.


well, the good news is in NY the dealer, by law, has to give a 30 day warranty with any used car, so all of this isnt costing me a penny and they can dump however much money into it they want for all I care. But I just want my truck back and fixed.


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## brad96z28 (Aug 21, 2005)

MikeRi24;1092916 said:


> well, the good news is in NY the dealer, by law, has to give a 30 day warranty with any used car, so all of this isnt costing me a penny and they can dump however much money into it they want for all I care. But I just want my truck back and fixed.


Lol in that case I hope the throw all the new parts at it they have Then they perform the re learn.It all depends on the tech that u get. It just sucks going back again when u need ur truck to work.Its a good truck and engine. I would not let this mishap take away from the truck. Let us know what they say,


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## MikeRi24 (Dec 21, 2007)

brad96z28;1092936 said:


> Lol in that case I hope the throw all the new parts at it they have Then they perform the re learn.It all depends on the tech that u get. It just sucks going back again when u need ur truck to work.Its a good truck and engine. I would not let this mishap take away from the truck. Let us know what they say,


oh trust me I am a pretty hardcore GM guy. I was raised on GMs and I can never remember a CEL in any of mine or my parents cars ever so even if these problems could not be resolved and I had to get another truck it would be another Chevy without a doubt.


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## CharlesW (Oct 13, 2010)

*Random Misfire Code*

While I am no by means an expert, I have had this same code on two different vehicles.
Both were GM V6 engines and my experience may have nothing to do with your problem, but.........
One was a leaking intake manifold gasket, the other was a leaking head gasket.
Replacing the manifold gasket was around $600 in 2002, replacing both head gaskets was around $1,000 in 2004.
Stay after the dealer to actually be sure the problem is corrected. Keep all the paperwork in case you need to have something fixed after the warranty period expires.

And yes, some of us never learn. We presently own 4 GM vehicles.


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## Polarisrider (Sep 4, 2009)

mine was in Tow/Haul mode yesterday too when it came on. keep us posted and let us know what it is they did to fix it when you get it back.


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## MikeRi24 (Dec 21, 2007)

CharlesW;1093033 said:


> While I am no by means an expert, I have had this same code on two different vehicles.
> Both were GM V6 engines and my experience may have nothing to do with your problem, but.........
> One was a leaking intake manifold gasket, the other was a leaking head gasket.
> Replacing the manifold gasket was around $600 in 2002, replacing both head gaskets was around $1,000 in 2004.
> ...


I have read it also may be the intake gasket and thats a common problem with the 6.0, so it doesnt sound too far fetched. I'm about to call the dealer here in a minute and see what they came up with. I have 4 messages on my phone right now from people who want plowing estimates, and no truck to go do them. this sucks!


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## MikeRi24 (Dec 21, 2007)

just got an update from the dealer. they switched all the coils around to see if the same code comes up for the right bank as it does the left bank. if so then its a problem with the coils. it not, they are going to order a new PCM for it, which could take a few days. great.


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## 70monte (Feb 5, 2008)

I thought they just installed all new coils. If so, I doubt its the coils. Problems with the fuel injectors can also cause a random misfire code. Have they checked the fuel injectors?

Wayne


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## chicagofella (Oct 23, 2010)

This is AMAZING, I have silverado 2500hd 2006 with 65k miles and my engine light started to flash and engine shut off. I took it to so many mechanics and everyone was saying it was the Mass airflow sensor, engine computer, bad gas. Finally even the dealer had a hard time finding why two cylinders were misfiring. Compression test on the bad cylinders was good. Compression test on other good cylinders revealed a spring broke inside the valve and caused a lot of damage. They said i need a new engine. LOL . The reason i went with a newer vehicle was to avoid problems and here I am....I used the truck very little for snow plowing last season. I am waiting for another mechanic to really take it apart to find out how much damage there is.


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## MikeRi24 (Dec 21, 2007)

the thing that throws me for a loop is throughout this whole thing, the truck runs fine. Light on or off, there is no change in the way the engine runs, the fuel mileage, or anything. It went on again yesterday, and then went off again today. Its going back to the dealer again on monday, I don't even know anymore!!


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## hockeypro1411 (Dec 13, 2008)

I'm guessing the light comes on when the engine revs to about 2000-2500? It's a very common problem that is solved about half the time with a crank re-learn from the dealer. Here's some more reading..

http://www.gm-trucks.com/forums/index.php?showtopic=120645

http://www.gm-trucks.com/forums/index.php?showtopic=114352&hl=p0300

http://www.gm-trucks.com/forums/index.php?showtopic=68294&hl=p0300


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## brad96z28 (Aug 21, 2005)

Like I said a few days ago.


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## Motorman 007 (Jan 11, 2005)

brad96z28;1092904 said:


> Ckp re learn almost alwyas cures multiple misfires





brad96z28;1095750 said:


> Like I said a few days ago.


Sorry but I didn't get that from your post either.....just saying....


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## MikeRi24 (Dec 21, 2007)

brad96z28;1095750 said:


> Like I said a few days ago.


I've been suggesting this to the dealer everytime I take it back. they keep going to the ignition system, and keep driving it because they think at some point they will miraculously actually get it to misfire. I know the first time they had it, they re-flashed the computer and updated it, will that re-program the cam sensor also?

anyway, its back, they have it again. at least this time they gave me a loaner truck. I told them until you are 100% sure you have fixed the problem, dont call me to come pick it up because if I have to being it back 1 more time its going to be with a lawyer and you're taking the truck back and giving me my money back and I will go elsewhere for a new one.


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## mickman (Jan 24, 2001)

Ive been having this problem for years on one of my 2003 2500hd 6.0L. We just changed plugs, pcv, air filter & wires for misfire code. Light comes back on or flashes. Had code read today to see WTF, & it said Mass air flow sensor. Great deal to replace it for $80.
Guess what, yep, light is back on. I thought it was tranny before, but just put in a new Jasper. But now I know how I'm going to fix it.....electrical tape on dash like people do to block out they're blinking clock on a vcr.


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## 2serious (Nov 16, 2010)

i got this awhile back also.turns out it was the intake tube after the mass airflow sensor right by th throttle body. that clamp came loose...who knew until i used a smoke machine on it to see it it was a intake gasket.


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