Rough idle, check engine light & More

My Avalanche is a 2008 (31,000 miles) and about 3-4 days ago, I noticed a rough idle.  I drove it about 40 miles this morning and the service stabiltrack and service traction control reading came up on the dash.  I went a little further and the check engine light came on.  I headed to the dealer which was about 30 miles away. 

I was on the highway and noticed the volt gauge was slightly lower than usual.  It is usually dead on 14 volts at the 12 o'clock position of the gauge, but now it was at roughly the 11 o'clock position.  I thought maybe the alternator was having a problem, so I turned all the accessories and the AC to high to see if the extra current draw made the volts drop more.  This had the reverse effect.  The voltage gauge gradually went back to 14 volts.  I then turned the extra accessories off and turned the AC down to low and the gauge gradually dropped back to the same position.  I put the AC on high and it gradually climbed to 14 volts again.  The truck seemed to run fine on the highway.

I dropped it at the dealer.  The service manager just called me back and said the truck was not firing on the #1 cylinder.  He said they pulled the plug out and it was fouled with a black color.  He said they called GM and GM wants them to pull the valve cover.  I asked if it was a compression problem or a ignition problem and he would not say either way.  He did say that GM had a technical bulletin on this and that they had to go through GM's procedure for GM to tell them how to proceed.

Does anyone have any ideas or is anyone aware of the TB he is talking about?

He will call me back tomorrow and let me know what they find.

2008 TSBs listed here

They made several checks and determined the plug was oil fouled because of a sticking ring in the #1 cylinder.  GM said to put a new plug in it and return to me.  The dealer said they will contact me when GM has a permanent fix for it.

This has happened to my 08 Avalanche twice in 6 months. They are blaming it on lifter problems. The first time it happened they had to replace the entire left side of the engine. It ended up causing cam damage. This time they say it is only limited to cylinder #6. The same thing occured, I was driving and the dash lit up with, stabili trac, engine light, traction control. They tell me that the engine would not change from the 8 cylinders to the 4 cylinders which was causing the rough idling. At speeds the engine was fine.

The first run with the dealer was 31 days and I am into 16 days now waiting for parts.

I just posted above on this topic. My new '09 had the same exact problem at 7933 miles just  last week. Service bulletin #PIP4568H addresses the problem and the fix is to replace ALL of the lifters on both sides even though only cylinder 1,4,6,7 are involved. This has to do do with the AFM. The problem is collapsed valve lifters and the valve lifter oil manifold. mine was bad on #6, no compression.

I was on vacation pulling my travel trailer when all the things described ; misfire, no power, check engine light, stabilitrack light, traction control light. I was able to limp into a campground and got it towed by GM Roadside. It was a 3 day fix and the parts were overnighted in from Atlanta to Athens TN. 

Mine has not had anymore problems yet and I have not heard back from the dealer.  If anything happens, I will post up.

cfleming said:

This has happened to my 08 Avalanche twice in 6 months. They are blaming it on lifter problems. The first time it happened they had to replace the entire left side of the engine. It ended up causing cam damage. This time they say it is only limited to cylinder #6. The same thing occured, I was driving and the dash lit up with, stabili trac, engine light, traction control. They tell me that the engine would not change from the 8 cylinders to the 4 cylinders which was causing the rough idling. At speeds the engine was fine.

The first run with the dealer was 31 days and I am into 16 days now waiting for parts.

Click to expand...

  exact same problem with my 08 LS 5.3L (AFM) with 22K miles on her.  Day 9 and still a week away for parts.  Got the same check engine light with the stabilitrak traction control warning.  Service Dept says its lifters.

Well, my truck fouled the #1 plug again on Monday.  Took it to the dealer yesterday and they said it was oil fouled.  They performed bulletin #10-06-01-008B.  They removed the oil pan and installed a shield on the AFM valve.  They also filled the cylinders with fuel injection cleaner for 2.5-3 hours to clean the rings.  The bulletin is for engine oil consumption.  Bulletin says that if oil consumption is greater than 1 quart in 2000 miles, replacement of the pistons and rings will be required.

The truck has 43,000 miles on it. 

My '08 Avalanche LTZ suddenly went into rough idle yesterday while we were out of town on vacation. We heard a "clunk" noise from under the car (sounded like a stone thrown up by a tire) then the truck started running rough. The dash display showed an intermittent check engine light. The Service Traction Control/stabilitrak notice was scrolling in the dash display, and the stabilitrak light was on. When we stopped at a light, the idle was so rough the truck was actually shaking. Pulled over and called the OnStar emergency number. They directed us to a Chevy dealer only 2 miles away. I was hoping a sensor fell off or something. No such luck.

The Myrtle Beach Chevrolet service advisor had the truck looked at immediately even though we arrived at 4PM, and got us a ride back to our hotel. He called to tell me that the problem is a stuck valve. The repair will take about 3 days. He wants to replace the parts and check the other engine components (camshaft, etc.) for damage. Glad we have the 5 year/100,000 mile powertrain warranty. The repair will cost me travel time and gas, since I live 190 miles from the dealership. GM is giving us a free rental car.

I will show the service advisor the info on Service bulletin #PIP4568H posted by Specs on 9/2/10. Thanks, Specs.

I had my truck back to the dealer 700 miles ago.  I took it in because the oil was over 2 quarts low.  Service writer said he thought he could get GM to go ahead and do the rings.  GM said no and made them change the valve cover.  GM did say if the truck continued to use more than one quart of oil per 2000 miles, they would do the rings.  I have about 650 miles on it since then and the truck is almost a quart low.   

So I bought my av. with 71k on it 3 weeks ago. Just yesterday it started missing on one cylinder and I got all the accompying alarms. I ran it out to the dealership and they said #3 cylinder has no compression. They are going to pull that cylinder. I'm sure they will call me soon with what the issue is and what they are going to fix. My concern is this, if it happens to one cylinder, isnt the chance of it happening to all the others pretty high? I am out of gm's warranty and only have a 3 month through the dealership. I have had this rig for 3 weeks and have had it in the shop 3 times already. Not real impressed with quality so far. I guess I'm gonna have to spring for some kind of extended warranty because this thing is broken more than it works.

I have been going thru the oil consumption problem since July of '11 with my '08 LTZ. The 1st time I had it in the shop, (at 44K miles), they added a deflector shield in the oil pan and cleaned the carbon out of the cylinders (this was done by pouring a cleaner into the cylinders thru the spark plug holes). After this work was done the service manager told me to keep an eye on the oil and maintain a consumption log, checking oil level at every fuel fill-up.
It didn't take long to see that the work performed had done nothing to correct the oil consumption problem with the engine still going thru 1qt every 1200m or so.   After logging the oil consumption for approx. 6K miles I took the Avy back to the dealer and was told that I would need to track the oil consumption for at least 10K miles.
After doing some searching on the web I found a post with a GM corporate bulletin, concerning oil consumption, and saw no requirement for waiting 10,000m prior to them trying another fix. I met with the service manager the next day and told him what I had found out - we made an appointment to get my truck in the following day.
This time they replaced a valve cover, with a redesigned baffle, on the left bank of the engine. I asked the service manager why they were doing this to my '08 since the GM TSB, that the original work was described under, specifically stated that the new valve cover was to be used only on the '09 model years and not the '07 or '08. I was told that there was a brand new TSB out although he could not find the TSB# for me.  Not completely trusting the service manager I contacted GM customer service to inquire about the new TSB. I was told that they would check on it and get back to me. When they called back I was told that a new valve cover is the new fix but once again received no TSB# to reference.
Status = still consuming approx 1qt every 1200miles with yet another visit to the shop coming up!

I stopped by Terry Labonte Chevrolet this morning to show them my truck continues to use oil.  2000 miles and it is over 1.5 quarts low.  They added oil and are scheduling a rental car for me so they can install new rings.  Hopefully GM will not come back and tell them they need to change the tail pipe hangar or rotate the air in the tires before they can do the rings.

I am very frustrated with GM's procedure.  I think the dealer has done what they had to and I am satisfied with them so far.  They did tell me this morning it will take probably 2 days to do the work and that they have done 7 or 8 of these.


wright4thepow- You may want to double check on your GM warranty.  If I am not mistaken, you are covered for 5 years or 100,000 miles.  I am sure someone else here can verify that if it is correct.

***Update***
Dropped my truck off yesterday at 7:00 am.  The dealer set me up with a rental vehicle and I told them to keep it as long as they needed, I just want it fixed.

They called me at 5:40 pm yesterday and said my truck was ready.  They installed 8 pistons and ring sets along with other miscellaneous parts.  They also had to replace one spark plug (8 would have been better).  I could not believe they got it done in one day.  Service writer said they had 2 guys on it all day.

I picked it up this morning.  In 2000 miles, I will know if it is any better or not.

So the dealership has had my Av for week. They are waiting for parts I guess. They are swapping out all the lifters, as well as putting the deflector shield in the oil pan and replacing the left valve cover with the one with newer baffles in it. All the same stuff that you had done STA. My concern is that this will not fix the underlying problem. I sure wish I could get a look at what that TSB says. I only have about 2 months on my warranty left and that may not be enough time to determine if I have oil loss or not. Please post some updates after you get some miles on your new rings and pistons.

Found it. The TSB details are posted on this forum.

http://www.g8board.com/forums/showthread.php?t=44552

And Here

Oil Consumption On Aluminum Block Engines

***Update***      After the new pistons and rings, I put about 4500 miles on the truck and it did not use any oil.  I thought great, everything is good now.  I had several problems with the truck, but I thought I could live with it now.  Then last week, I was leaving work and pulled out into traffic, the truck made a loud clunk noise and went into low power mode.  I baby'd it back to the dealership and they said it sounds like the transmission. They called me the next day and said it was not the transmission, but the fuel pedal went bad.  This item was out of warranty, but they said GM "good willed it" due to everything I have been through.  They then tried to sell me a $300.00 brake job and a $37.00 parking light.  I told them to zip it up and I was done.  I really feel like the major problems were behind me but I had no confidence in the truck anymore.  I took it to CarMax and they gave me a number I could live with, so it is gone.

my av is misfiring and all the bells and whistles are going off.  Going in for service tomorrow.  Once it's fixed i'm done.  No more GM.  Burning oil, not a very nice person dealers, and now who knows what.  Brutal.

My 2011 was misfiring on cylinder 7 and idling rough. The dealer replaced the driver's side valve cover. The plug was caked in burnt oil. The dealer said I was getting misfires on cylinders 1 & 7. My autotap does not support the gm enhanced parameters on this truck, so I can't see the real time misfires. I can only see the misfires once a code is set.

I am about 1/2 a quart low at 2000 miles since the last oil change, which is pretty normal. Hopefully, this fixes the problem. I had the plug go bad 8000 miles ago as well, but that time they only replaced the plug.

I am going to pull the plug in a couple of weeks to see if it has any evidence of oil on it.

My idle is still not very smooth. It is no where near as bad as it was while I was getting the misfires. Maybe I am paying a lot more attention to it now that the plug went bad again.

I just dropped off my 08 LTZ with 75,000 miles on it last night. I've been having oil consumption issues for quite a while now, then yesterday started the rough idle along with StabiliTrak and traction control warnings, and the check engine light was on. The dealer said they should be able to check it out by this afternoon to see what is going on. I just hope it's still nder warranty!!

Dealer said cylinder 4 was dead and they are replacing the cam as well as a complete set of new lifters.

Maybe they repair engines differently than almost 40 years ago when I did a few valve and ring jobs, but I never heard of just throwing new rings on pistons without working on the cylinder walls.

On an engine with relatively low miles you might get away with a standard ring set.......but you also have to address the cylinder walls......even if there is no scuffing or gouging, the walls have to be measured for out of round and must be rehoned.....if you fail to break the glaze by rehoning the wall, the new rings will not break-in/seat properly and soon you'll have oil consumption and maybe even compression issues. In an engine with miles you probably can't get away with a simple rehoning because with wear the cylinder walls become out of round and proper oil retention and compression can only be assured by reboring the cylinders oversize and using oversize rings and possibly larger pistons if the wear is extreme. And consider how much damage was done to the cylinder walls by stuck compression rings which fail to move within the piston ring grooves during the time and miles when they first clogged/seized and when the oil consumption really became apparent?? Rings must move within the piston grooves so the compression rings can give maximum compression and oil rings can squeegee the excess oil off the walls back to the crankcase instead of burning in the cylinder. Appears to me that once the oil burning is apparent, nothing short of an engine rebuild, not just slapping in new rings will last long term, but that's only my 2 cents worth of opinion.

I had worked on and rebuilt only on iron block engines where reboring and use of oversized pistons is possible.....I don't know if that's possible on aluminum engines which use iron cylinder liners......which I hope is what Chevys do because the last all aluminum engine without iron liners that Chevy made went into the Vega.....they  soon burned more oil than gasoline because the microscopic sapphire coating on the cylinder wall wore off in places and the aluminum cylinder walls became gouged....and just like the Corvair, once it was fixed it was too late once the vehicle had a bad reputation.

On my 07 I had a misfire on #3 so i changed the coil and new plug and wires,  after i got p0300 then just recently i got p0303 for #3 again. And all my lights are flickering. I asked a guy from work who has the same year, he said that he spent $2k before they figured out that the pedal assembly was causing his problems. I ordered one and now just waiting for it to get  here and hoping that this my truck too

Just great! S/T lights go on and off and rough idle. 60k miles on my 08 Avy.  Cleaning carbon in throttle body  and new plugs was no help with the idle issue
Just replaced the evap solenoid to clear code p0449. That was easy but didn't fix the idle/ S/T lights! !

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