I drove the car 2 days ago and it was working perfectly.

With the cooler weather I burned a new prom to adjust the start up enrichment that was based off a known good program I have been running all summer.

It had trouble starting right from the start. Once I got it to start by holding the gas pedal down, I took it for a drive. It was terrible.

The car had now power at all. Holding the gas pedal down while driving only caused the RPMs to go up very slowly. Around 4000RPM at WOT there was a backfire so loud it made a shotgun sound quiet.

I've tried spare chips and the factory chip I had laying around with known good programs and the car acted the exact same with all of them.

Is this a prom, memcal, PCM problem?

 

For anyone who has been reading, I replaced the ECM with a known good 730 ECM and the car is showing the exact same symptoms as before.

I guess it is either a bad PROM program or the calpack/memcal whatever its called.

 

Also pulled codes and only got code 12. It seems a little weird that a moderately modified engine isn't throwing any codes..