2010 LT hard to start when cold, have to give it some gas.

wildaz · Jan 12, 2013

Let me start by saying hello and that this is my first post on the forum. I'm also relatively new to the "truck club", I just purchased my first truck, a 2010 Silverado LT Extended Cab 4x4 about two months ago.

So the reason for my post is that I have started having a hard time starting my truck after it sits overnight or for several hours between drives. This just started happening about a week ago and sometimes it will start but the RPM's will drop very low, almost to a stall, and then it will rev back up. Other times it will start and then it will stall within a second or two. When it does stall I will have to give it some gas when I start it again and then it will stay running and once it is running it runs just fine.

Does anyone have any idea what could be the culprit? It almost seems like it is a fuel pressure issue as it will start right up if there is only a short period of time to a couple of hours between drives.

The only modifications I have made are a K&N cold air intake and a Borla cat-back dual exhaust. I have an OBDII code reader and there are no codes.

Thanks!
Dustin

EKinMN · Jan 12, 2013

Couple ideas.....
Clean your MAF sensor. Sometimes with K&N, if the fiter gets over oiled, the MAF will clog. See this post:
How to Inspect and Clean a Mass Air Flow Sensor (MAF)

Another possibility, if you have more than 30,000 miles on the truck, or don't use high quality fuel is a dirty throttle body. See this post:
How to Clean your Throttle Body

WELCOME to the site!

wildaz · Jan 13, 2013

Thanks EKinMN, my truck only has about 13,000 miles on it but I have some MAF cleaner already and will pickup some throttle body cleaner today and let you know if cleaning either of those helps.

EKinMN · Jan 13, 2013

Be sure to disconnect the battery and let it sit a while when you do this. Resetting the ECM by disconnecting the battery is always a good idea when ya do these cleanings.

Let us know.

wildaz · Jan 13, 2013

All done, there was a little soot in the throttle body but nothing I would consider significant. I will see how it starts up in the morning the next couple of days and report back.

Thanks!

zombiehunr · Jan 13, 2013

I just resolved this same issue two days ago. Turns out the alcohol content in my fuel was extremely high, causing the symptoms you described. do you have a check engine light the first few minutes after starting?

wildaz · Jan 13, 2013

No, no check engine light.

However, I was getting a light the one time I decided to fill it up with E85 since it is a flex-fuel vehicle. When that was happening I scanned for the codes and it said it was running lean in both banks. The next time I filled up I went back to mid-grade gas and I haven't received any check engine lights or codes since then.

zombiehunr · Jan 13, 2013

try different fuel first and see if the problem persists, my truck threw a code once. The dealer can check alcohol content with their scanner

zandron263 · Jan 14, 2013

I had the same issue last year with the high alcohol content in the fuel. I was running E85 from time to time to see how it worked. The cost savings were negated by the lower MPG I got. I always followed the owners manual directions to run the tank as low as possible when I switched between E85 and gas.

The dealer fixed the issue under warranty and I stopped using E85 and I have not had a problem since.

wildaz · Jan 14, 2013

zandron263 said:
I had the same issue last year with the high alcohol content in the fuel. I was running E85 from time to time to see how it worked. The cost savings were negated by the lower MPG I got. I always followed the owners manual directions to run the tank as low as possible when I switched between E85 and gas.

The dealer fixed the issue under warranty and I stopped using E85 and I have not had a problem since.

Zandron263, what did the dealer fix under warranty?

zandron263 · Jan 14, 2013

I will have to look for the paperwork when I get home tonight to tell you exactly what it was. I think they just made some computer adjustment to get the alcohol content in the fuel correct.

zandron263 · Jan 15, 2013

Ok I found the paperwork. They reset the alcohol content and cleaned the upper intake system. Removed fuel feed line and fuel pump module to run top engine cleaner at 800 RPM's. Remove and install factory fuel line and module fuse and clear misfire code. Then it was all reinstalled and they let it sit overnight to get a cold start and there were no more misfire codes. Hope it helps you out.

wildaz · Jan 15, 2013

Thanks, I tried some different gas when I filled up after cleaning my MAF and throttle body so if that doesn't fix it I will pay the dealer a visit.

runyanzoo · Jan 25, 2013

my 2011 sierra was doing the same thing and I explained to them about the alcohol sensor and they said it might be fuel pump. but left it and turned out it was the intake gasket was leaking, and was told that the cold weather can make them contract and cause a leak. so far no problems.

GM Customer Service · Jan 26, 2013

Thank you for posting these concerns. Please keep us updated if you any issues getting a vehicle repaired satisfactorily at the dealership. If you send a PM, please include your VIN#, name, situation, current mileage, contact information, and the dealer name. I hope everyone is doing well, despite any car issues. Thank you.

Matt,

GM Customer Assistance

wildaz · Feb 22, 2013

Hello again,

It's been a while but I finally got my truck into a dealer today and what they found was that the computer was reading the alcohol level in the fuel at 56% but when they tested the fuel it was only 10% alcohol. They reset the computer and hopefully all my problems will be solved. I will know tomorrow morning when I go to start it up after sitting all night but I'm pretty sure I noticed an increase in performance on my way home from the dealer, then again it could be the placebo affect.

FARMBOI · Jun 1, 2015

Have you had any problems sense they reset your computer? I have had the same problem with my truck! they reset my computer too and its starting to act up after a few weeks.. I also have a cold air intake

2010 LT hard to start when cold, have to give it some gas.

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