My 89 MAF ECM, 165 came stock with an APYN prom. I also have an AUJM and a ARAP prom. When programming chips using stock bins I noticed and now wonder why ARAP checks the "calculate BPW don't use table" where APYN and AUJM doesn't?
GW

 

This is from memory: but if IIRC that bit doesn't matter in $6E. The $6E mask doesn't have the PW tables to use, it can only calculate the PW from the airflow. The option bit in question is ignored in the code.

RBob.