1991 Oldsmobile 88 High block learn values and maf sensor

Hi, I have a 1991 olds eighty eighty royale. Using the tech 1 scan tool, the block learn values are almost at or at 150 while freeway driving. Idleing, the block learn will go to 150 when it is in open loop mode, and 144 in closed loop mode. The factory service manual tells me to unplugg the maf sensor and if lean condition goes away, replace maf sensor. Well I unplugged the sensor while in closed loop mode, and the block learn went from 144 to 129. I have replaced all 6 injectors with summit racing accel brand injectors 19/lbs and hour. The engine runs better in open loop mode, closed loop mode at idle is not as smooth. Things I have tried. Tested fuel pressire. 35psi running, 43 when revved. Couldnt find any vacuum leaks, New o2 sensor, sprayed throttle body inside with b12 chemtool injector cleaner with mass air removed. Sprayed mass air flow cleaner at sensor with engine running. New spark plugs. new fuel filter, new fuel pressure regulator, spark plug color is white. Lean condition I guess.