Ok Chevy, I'm begging for some serious help and better facts. I have been working on this problem for almost a year with the dealership. This problem is intermittent so I understand its hard to solve. They even had my truck for a whole two weeks and I'm still struggling with this problem and I need it solved. The truck as a new accelerator, actually the third new one. It has a different computer and they say they have checked all the wires. Whenever it faults, I move the wires around and things work a little for awhile and then, down again. Its worse when I'm on the highway and seems like this is a common issues. Please help me and the dealership fix this once and for all. I don't need any more excuses. The current code is P2138, P127. Every time it happens I read the codes and screen shot them so I have an extensive record.

 

I had same issue with my 2010 Avalanche, but with a clanking sound as well. It ended up being the Cam lifters were getting stuck. So with motor at 145K miles I just decided to get a new motor since I never plan on selling the truck, and has been working great ever since. I know that may sound an expensive option but worked out for me.