Actually, it was more like a Miata transplant, because i took my drivetrain and put it in a non-totaled Miata.
Even on the stock computer, when i rev it and hold it around 2k rpm, the car starts surging up and down exactly 250 rpm. It's very precisely rhythmic up and down and will stay that way until i rev past that point (which it doesn't immediately want to do) or let the revs drop.
Also, the car has a severe problem transitioning into boost and bucks like a wild horse at cruising speed.
I have tried:
Checking for vacuum leaks. I get -25 at vacuum, and the vacuum isn't effected much by the surging.
I have checked all my ground points and verified good connectivity of the O2 sensor.
I have hooked up my laptop to the emanage/autotune and confirmed the proper 50% throttle position (O2 sensor voltage) recorded by the Emanage.
Consider that the entire drivetrain was swapped from the old car, from the engine and transmission, the rear end, my fuel pump, Vortech FPR, and my Emanage and autotune. (We're talking months of coming to work on this thing on the weekends.)
After the installation of the Emanage, the problem is still there.
Granted, the only thing i used on the new car was the ECU, and I did reuse my old throttle body even though it might have gotten damaged in the wreck. I'm going to try and change those out first.
Any other suggestions?