This is how I handle Fuel trim on MAF cars.

Graph the following items - in side by side 1. Engine RPM 2. Calc engine Load 3. Throttle Position 4. MAF in G/S 5. B1S1 6. B2S1

Test Drive the car first at Idle - RPM at 800, GS should be around - 5.32 O2 are swi... Login to read more.