Trucks a 5.3 automatic. When you first start it after it sits for short or long periods of time it will occasionally just fall flat on its face when you try to accelerate.
After it does it once or twice it runs fine, doesnt do it everytime. Fuel pressure is 55psi with key on non run, 45psi cranking and 55 at idle and starts climbing under accel right away.
Only trouble code is for an evap leak. I havnt had time to start checking sensors individually with a volt meter or do much yet so i figured id get some input.
Most forums are saying its MAF related and there was a tsb for a reprogram but those trucks all showed the symptom at low mileage. This one just started at 192k miles.
Checked for crud getting sucked up into the fuel filter?
Sounds air related. MAF (yes, I know), or idle air control. Throttle position would probably be a more constant issue, but you may want to consider it.
Fuel filter has 17k on it but is on the list of things too change because cheap. Ill likely check the idle air control valve via volt meter if i can find specs.
For MAF i think the easy check is to make my wife drive it while i play with the scanner since it doesnt record.
Thanks for the idea's im really just trying to come up with a plan of attack more or less. Wont rule anything out without checking it.
I would start by checking the tps with the scan tool because easy. Just push throttle slowly and steady to the floor (engine off) and make sure it reads accordingly. Maf is hard because even when it's right it's erratic, and when the truck stumbles you have to ask yourself, did it stumble because maf went wonky or vice versa? But clean the maf and the throttle body. Oh and check for intake gasket vacuum leaks. Those were common and caused lots of cold start drivability problems on those trucks. Good luck brother.
