Idontknowanymore

09 gmc sierra 5.3l, 6 minths ago check engine light came on blinking, dash screen said stablelink and tracktion control off. engine running rough at idle, trouble code cylinder 6 misfire. shop replaced lifter and head gasket, cost me $1100, part and labor warranty for 3 years included. Bought diablo tuner to deactivate afm/dod. Dash screen showed that it was in v8 mode all the time after that. Win in my book!!!! Not so fast... All was fine until 2 weeks ago, same exact symtoms/issue, shop replaced same parts as the first time, truck was running fine. Check engine light came on after a few miles down the street.hooked up my scanner, trouble codes p0171 & p0174 (bank 1& bank 2 running lean) truck felt like it was running fine though. Brought truck back to the shop. They smog tested it, supposidly no vaccum leaks. Cleared code. Drove home, shut truck off, truck was off long enough to cool down completely. Drive to the store later that day, light came back on,same codes. Brought truck back to shop next day, they can not figure out why its throwing those 2 codes after 5 hours looking at the truck. I restored factory tune, light when away. Came back a few miles later, lol. Switched back and forth between stock tune and diablo tune because installing the diablo tune is the only way to turn off afm/dod. Every time i switched tunes light will go away on the first drive and will come back on the second drive after shutting the truck off. Didnt seem like it was hurting anything to drive it with the light on,truck was running perfectly fine. Just came back from the store and on the way home, guess what!!! Dash lit up and now truck is misfiring again and it limped half way home.... i dont have the slightest clue on what to do beside take the truck back to the shop and see if its still covered under their parts and labor warranty they gave me... im at a complete loss...any help at all would be appriciated, thanks

09 gmc sierra 5.3l, 6 minths ago check engine light came on blinking, dash screen said stablelink and tracktion control off. engine running rough at idle, trouble code cylinder 6 misfire. shop replaced lifter and head gasket, cost me $1100, part and labor warranty for 3 years included. Bought diablo tuner to deactivate afm/dod. Dash screen showed that it was in v8 mode all the time after that. Win in my book!!!! Not so fast... All was fine until 2 weeks ago, same exact symtoms/issue, shop replaced same parts as the first time, truck was running fine. Check engine light came on after a few miles down the street.hooked up my scanner, trouble codes p0171 & p0174 (bank 1& bank 2 running lean) truck felt like it was running fine though. Brought truck back to the shop. They smog tested it, supposidly no vaccum leaks. Cleared code. Drove home, shut truck off, truck was off long enough to cool down completely. Drive to the store later that day, light came back on,same codes. Brought truck back to shop next day, they can not figure out why its throwing those 2 codes after 5 hours looking at the truck. I restored factory tune, light when away. Came back a few miles later, lol. Switched back and forth between stock tune and diablo tune because installing the diablo tune is the only way to turn off afm/dod. Every time i switched tunes light will go away on the first drive and will come back on the second drive after shutting the truck off. Didnt seem like it was hurting anything to drive it with the light on,truck was running perfectly fine. Just came back from the store and on the way home, guess what!!! Dash lit up and now truck is misfiring again and it limped half way home.... i dont have the slightest clue on what to do beside take the truck back to the shop and see if its still covered under their parts and labor warranty they gave me... im at a complete loss...any help at all would be appriciated, thanks