Tried bumping the upper end of my IAC/airflow table (100% airflow => 220 steps). I heard the IAC move with key on and the PCM never blinked to confirm the prom was ok. Now the PCM won't load any prom or even the factory memcal (so I switched over to my spare PCM)

I did neglect to do an IAC reset before trying that chip, but.. damn. I was hoping to improve my initial startup transition from crank->choke->OL with a bit more fuel+air during crank & choke.

Coincidental failure, or is there a hard maximum for the IAC?
Stock is 150 steps, the 8bit value allows 255...

 

i don't see how that could have caused it, considering that when you shut the ignition off, the PCM commands the IAC to fully open and close(i may have this backwards), then back to the position it is supposed to be at for cranking.

at least, that's how it works in $A1.