Got a problem with a Spirit R/T that a local friend now owns. It was recently upgraded with a bunch of go-fast stuff including:
T04E 50-trim turbo
FMIC
FWDP Stg 4 SBEC
+40 injectors
3-bar MAP
After installing the FWDP SBEC, my friend said it had a random misfire and backfire. I drove the car today and sure enough, it had a random misfire where the power was cut (like total ignition cut) and the tach would drop to zero when this happens with a small backfire out the exhaust. I believe the backfire is due to the unburnt fuel in the exhaust as a byproduct of the ignition cut. The car runs pretty good (when it does run) and I don't believe there are any timing issues.
Tonight it got so bad that the car will barely start. If it does, the ignition is dropping out so much it stalls after a few seconds and the tachometer is freaking out. I checked the codes and got 25 (AIS motor) and 53, which my OTC scanner describes as a ECU self-test failure. Is the code 53 something I should expect with a recalibrated SBEC or is this sounding like a SBEC failure? I have poked around the wiring harness a little bit but so far can't find anything obviously wrong. All the fuse links seem good as well.
Any ideas?