My buddy and I swapped an S4 out of my running racecar and put it in his FB racecar.

We took the entire longblock and all accessories together and put them in the FB. This includes the computer, boost sensor, AFM, coolant temp sensor, etc. No emissions on this engine. It ran just fine in the other chassis.

Now, we can get the car to idle, but the minute that we try to rev it, it pops and backfires and will usually stall.

Any help is appreciated.

We did re-stab the CAS and lined it up properly. Haven't got a chance to put a timing gun on it, yet.