1991 olds eighty eight royale lean running

Hello I have a 3800 engine in this car(vin code c). While driving, the scan tool tech 1 block learn value is 150 on the freeway. sometimes drops to 148. Im trying to determine if I have a bad maf sensor. All new injectors and throttle body cleaned. Maf sensor is cleaned using maf cleaner. When the maf is unplugged at idle, the block learn will go down to 128-130, which is where it should be I think. Is this unplugging test a good way to determine if the maf is making it run lean?

Check the fuel pressure. Look for vacuum leaks, possible false o2 readings, dirty injecors, are all possiblities.