My suburban above one day just started stumbling up to about 2000 rpm then seems to catch up with itself and runs fine. When I drive on the interstate it sometimes pops a p0171 and p0174 code. last code it popped the other day was a p0101. I have replaced my MAF, EGR, Fuel pump and filter, Idle control sensor, throttle control sensor, pcv and checked for vacuum leaks a number of times just to be sure. Still stumbles until about 2000 rpm. I put a vacuum gauge on it and I pull low normal spectrum but it does say something about the timing might be off. Fuel pressure at idle is 54psi. Pump said working pressure should be 62 but that never happens and the truck ran fine before at this pressure. Does anyone have an idea? or do I have to submit the humiliation of taking it to the dealer.....


thanks all for any help you can offer!