When engine stopped MAF sensor is reading 0.28 gram / second.
Is this normal?
P0171 & P0174 codes present. 62 lbs fuel pressure holds for 5 min. No manifold leaks, power brake booster or vacuum accessories leaks. Engines runs smooth. No drivability or starting problems.

 

At idle the MAF should be reading close to the size of the engine 4-5 g/s.

How to Clean the GM Mass Air Flow (MAF) Sensor

 

Engine warmed up idling @650 rpm MAF reads 4.81


Bank 1 Long Term Fuel Trim @ 650 rpm = 23.67
Bank 2 Long Term Fuel Trim @ 650 rpm = 19.87


Far as I can tell its the original CSFI. Hoping the problem is the MAF reading too much air, causing the ECM to enrich fuel to the limit of the fuel map, triggering the Bank 1 DTC.