[biggsteve97]

I have an 03 Tahoe with the 5.3L, it has a slight stumble at idle as well as low power from idle to 3,000 rpm however from 3000 rpm to red-line no power issues. This is not as noticeable when the engine is cold it becomes more noticeable the longer you drive it. I have change intake gaskets, spark plugs, air filter, cleaned the throttle body, all four O2 sensors, fuel pressure regulator, fuel pump, and the evap vent solenoid and hose assembly. All of this changed nothing, still has a slight stumble at idle and low on power until 3,000 rpm. I have only had 2 codes in the past 2 months a P0101 mass air flow sensor circuit issue (2 months ago) and a P0430 bank 2 converter efficiency code. The P0430 code only came on after an hour of stop and go driving below 30 mph. That was 5 days ago and has not come back. On a tech 2 the mass air flow sensor is slow to respond but not slow enough to set a code. I can find no other faults. Could the mass air flow sensor cause all of this or am i possibly looking at a faulty cat or both? I am stumped and so are both Local gm dealers.