2011 Chevy Silverado 1500 Rough Start

batman06 · January 22, 2014

I clean my maf senor with a sensor cleaner thinking it had they oil from the fitter. But didn't work.

How do you check if ur intake gasket is leaking?

MikeNH · January 22, 2014

These trucks don't have ethanol sensors. They calculate ethanol content by adjusting timing and checking for knock.

mike94silverado · January 22, 2014

I'm going to ask specifically about the intake gasket as I still have powertrain warranty

GMCustomerService · January 22, 2014

Hello All,

I’m sorry to hear that you all are experiencing this problem with your vehicles. I would like to look further into your concerns. If I can be of any assistance, please private message me your VIN so that I can take a better look at your vehicles. Thank you.

Kristen A.

GM Customer Care

bassmaster · January 25, 2014

Well I took the advice about letting the tank run almost empty then filling it up with top tier gas, but that didn’t change anything. The problem still persists and has gone on now for about 3 months now. It does that rpm bog then idles rough as hell for about 15 seconds then it magically goes normal like something just realizes it’s not running right. It does that consistently every time on a cold start. Once it runs like a freaking tank for 15 seconds the rpms slightly jump then idles perfect. It’s really starting to piss me off because I or no one else has been able to figure out what is wrong with it. I’ve had the dealership and other mechanics look at it all too just be puzzled by it. I’ve tried it all. It is embarrassing to crank up because a 2011 $30K truck should not do that. The last thing suggested to me was to get and ethanol reset procedure done and have the fuel trims reset. He said that the truck thinks it running a higher percent ethanol than it actually is and the reason it only does it on a cold start is that is when it measures the fuel trims. I’ve yet to do that because I called the dealerships and they act like they have never heard of such a thing? So I don’t know where to turn now.

&CDFiXER% · January 25, 2014

When I had my 2011 it had similar issues that would come and go. The dealership could not find anything wrong but told me there was a recall or notice (never found it myself) out on a "fuel control module". They replaced that (free) with the understanding if it still acted up I just had to bring it back in. The truck started better than it ever had (crank for 3+ seconds then start before to less than 1 second and catch) and never had the other intermittent symptoms.

IIRC (and boy my memory isn't great, lol) I looked up where the module was and it is mounted either on the tank or on the frame rail near the tank. I might also have posted in here about it but I don't think anyone else had heard of the recall/service notice either.

UCABlackChevy · February 19, 2014

bassmaster,

Did you ever find out what the issue was? I have a 2010 with 30k miles that is exhibiting the exact same thing. The dealership replaced my throttle body (cost me $488: because the throttle body doesn't count under powertrain, takes some mental gymnastics to come to that ridiculous conclusion) and it still didn't fix the issue. Extremely embarrassing that my 3.5 year old truck with 30k miles sounds like an old jalopy when it starts.

bassmaster · February 20, 2014

bassmaster,

Did you ever find out what the issue was? I have a 2010 with 30k miles that is exhibiting the exact same thing. The dealership replaced my throttle body (cost me $488: because the throttle body doesn't count under powertrain, takes some mental gymnastics to come to that ridiculous conclusion) and it still didn't fix the issue. Extremely embarrassing that my 3.5 year old truck with 30k miles sounds like an old jalopy when it starts.

I totally feel the same way. I have tried near about everything. The trouble was that no one knew what it was, not even the dealership. It was because there were no trouble codes to lead them to something. The last thing that I have done seems to have fixed the problem. I took someones advice and ran the tank really low, and filled it up with ethanol free gas. I did this because the these trucks don't have an ethanol sensor because it costs too much according to GM so they designed them to do some type of algorithm calculation when the tank detects that it has had fuel added to it. During these first miles upon refueling it calculates the correct alcohol to ethanol ratio for the fuel, and if you read your owners manual somewhere it says this refueling process. The problem is that the fuel trim values are incorrect because it missed the calculation one time causing it to miss-calculate it every time after that. The reason for it miss-calculating is that you are supposed to run the truck for at least 7 miles or like 20 minutes before you switch it off. This gives it time to calculate it. The reason I went ethanol free was to totally eliminate the cause of the incorrect fuel mixture ratio by thinking there is ethanol. It says this is only necessary when switching from e85 to regular but I have never ran e85 in it. So when the engine is cold, it reads the fuel trims. That wrong fuel trim causes it to misfire like and do what it does. I will probably run another tank of ethanol free gas and the procedure just to be safe but I think I have fixed it and maybe this will help you.

bassmaster · February 20, 2014

http://www.gm-trucks.com/forums/topic/129554-2010-gmc-sierra-cold-start-problem/

http://www.gm-trucks.com/forums/topic/78169-e-85-refueling-events/

Check these threads out, they are also some good information.

amc31b · February 20, 2014

Hmmmmm... If running ethanol free gas solved the problem, I wonder if disconnecting the battery for 30 minutes and letting the ECM reset would have fixed it also? Something to try for next time maybe?

bassmaster · February 20, 2014

Hmmmmm... If running ethanol free gas solved the problem, I wonder if disconnecting the battery for 30 minutes and letting the ECM reset would have fixed it also? Something to try for next time maybe?

I thought the same thing. I tried disconnecting it for 30 minutes and nothing changed. I even left it disconnected over night and it didn't change a thing, so apparently those fuel trims are something that a soft reset (disconnecting the battery) of the ECM can't change.

mymaggiebell · February 21, 2014

guys...why i brought my truck in for lifter noise, was in part on how the thing started...very similar to what u r experiencing and at the moment cam and lifters were the blame. i thought too, battery possibly, especially with how cold this winter is, but it was ruled out.

batman06 · March 6, 2014

I haven't fixed mines yet still the same. But I always kept my fuel full so when it goes halfway filled it up. Like now I don't do it that's why it started happening. So I kept it full n started okay. But seems like now it dont matter now. Still starts weird. But it's just that one starts in the morning n after a long day at work. After starting it n starting it. Starts fine.

Gone Again · March 6, 2014

Have your dealer or someone with a decent scan tool check to see what ethanol content your computer is reading. Depending on what fuel you're using (not E85) you should see 10% or less. My 2010 5.3L was having exact same symptoms. Computer was seeing 58%. PCM is SUPPOSED to calculate ethanol content from info received from O2 sensors, fuel level indicator and vehicle speed sensor. We all know computers do things for no reason. Dealer tech did not know for sure what happened, all sensor outputs were good. A reprogram of PCM put reading back to normal (3%) and all is well.