# 05 6.0 2500hd check engine light



## ajracing81 (Dec 19, 2010)

So i bought this truck 2 months ago and have had the engine light on 3 times. First time . brought to a local shop and said it was a random misfire and said they havent had any problems with the 6.o and said it must have been a rare thing and cleared it. 2nd time brought it to the dealer and they scanned and said they updated the computer. I have had it flash a couple different mornings but wouldnt stay on. Today i was leaving town going down the hwy and a couple of miles out of town it came on and stayed on. Luckly i was going to where i bought it to get it washed(for Free) it started flashing and staying on steady alternating. So i got there they scanned it and came up misfire 1,5,6 and 8. Any ideas what would cause this?


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## mkwl (Jan 21, 2005)

Have you done plugs and wires on it yet? If not- I'd recommend it.... my '03 had the same issue about 2 years ago- plugs, wires, and intake cleaning took care of it (knock in wood).


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## m297 (Aug 27, 2007)

Had the same thing happen to me, it turned out to be the #8 ign module went bad.


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## ajracing81 (Dec 19, 2010)

Just picked up my truck. There saying that who ever put the k&n air fliter in the truck before put to much oil on it and it coated the mass airflow sen. and thats what is caused oil and dust to build up on it. So i put stock filter in and we shall wait and see. I have a feeling this isnt it.


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## tac48 (Jun 22, 2010)

Hopefully they did a crankshaft position sensor relearn. Have seen the relearn fix random misfires on the 6.0 many times. If it still acts up, make sure they have done that for you before going much further.


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## larboc (Dec 8, 2009)

ajracing81;1439364 said:


> Just picked up my truck. There saying that who ever put the k&n air fliter in the truck before put to much oil on it and it coated the mass airflow sen. and thats what is caused oil and dust to build up on it. So i put stock filter in and we shall wait and see. I have a feeling this isnt it.


I've seen K&N's foul MAF sensors several times even though the bad MAF sensor didn't trigger a code. Once on a '99 5.3 it caused some crazy shudder and shifting problems but didn't throw a code. While logging data with hptuners I could see the measured air flow rate jumping around and finally figured out that the MAF was the problem.

K&N=bad MAF sensor.


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## tmltrans (Oct 18, 2004)

*Random misfire.*

Try the plugs its easy and that's what it was on my 04 6.0L. Stick w/ a stock type plug the expensive Platinums I put in made it worse.


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## lawnmedic (Jan 9, 2004)

tac48;1439423 said:


> Hopefully they did a crankshaft position sensor relearn. Have seen the relearn fix random misfires on the 6.0 many times. If it still acts up, make sure they have done that for you before going much further.


Crank relearn.... Most common fix for this problem. Needs to be done anytime any "tune up" done. Takes my shop 2-3 minutes. They don't even pull it in.


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## DrakeSabitch (Jan 20, 2010)

how many miles on your truck? Mine has about 73k and I've been getting the flashing light when i accelerate on the highway around 70-75mph. The code reads for multiple cylinder misfire. Chevy reccomends a tune up at 100k, but I'm thinking I'm going to have to do one sooner than that. Im guessing you probably just need a tune up.


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## ajracing81 (Dec 19, 2010)

DrakeSa*****;1452320 said:


> how many miles on your truck? Mine has about 73k and I've been getting the flashing light when i accelerate on the highway around 70-75mph. The code reads for multiple cylinder misfire. Chevy reccomends a tune up at 100k, but I'm thinking I'm going to have to do one sooner than that. Im guessing you probably just need a tune up.


i have 55000 miles on it. Havent had the light come on since the air filter deal, until the other day i was going around 70-75mph and it flashed a couple times and then went out and did it again and never stayed on. Dealer ship said to keep an eye on it. Im going to change plugs today.


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## cubicinches (Oct 19, 2008)

I'd definitely have the crank re-learn performed before you throw any parts at it. Also, have the intake manifold gaskets checked for vacuum leaks. If you do change plugs or wires, use only OEM AC Delco parts... Otherwise you're just asking for more troubles.

Personally, I'd ditch the K&N filter... It's of little to no benefit, and the oil from the element only aggravates the MAF. Not likely the cause of a random misfire code though.


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## cubicinches (Oct 19, 2008)

Sorry... I see where you said you re-installed the stock air filter already. Smart move... Thumbs Up


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## DrakeSabitch (Jan 20, 2010)

ajracing81;1452390 said:


> i have 55000 miles on it. Havent had the light come on since the air filter deal, until the other day i was going around 70-75mph and it flashed a couple times and then went out and did it again and never stayed on. Dealer ship said to keep an eye on it. Im going to change plugs today.


How did you make out with the new plugs? Any difference?


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## ajracing81 (Dec 19, 2010)

well changed plugs (factory) and wires so we will what happens seems to run the same ill find out tom. night have to travel with it.


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## ajracing81 (Dec 19, 2010)

so the light came on again it seems to only come on when i go 70 mph because i drive to work everyday day going 60mph and never comes on. Im calling the dealer this morning to see if they can do the crankshaft sensor relearn.


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## DrakeSabitch (Jan 20, 2010)

Brought my truck in this past week to fix my blinking check engine light/misfire issue. The dealership relearned the crankshaft position sensor. Problem SOLVED.


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## sechracer (Nov 4, 2007)

DrakeSa*****;1475834 said:


> Brought my truck in this past week to fix my blinking check engine light/misfire issue. The dealership relearned the crankshaft position sensor. Problem SOLVED.


X2.. this had to be done to my new to me 05 also.


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## ajracing81 (Dec 19, 2010)

thats what they ended up doing to it.


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