intermittent ignition cut followed by large backfire

[oxymoron]

Hey guys , I got an 88 is . M50 injectors bimmerheads head with 274 cam. New plugs last year along with distributor. My wires have been on the car as long as ive had it along with ignition coil and o2 sensor. Anyways coil is reading 5900 and 5.9 ohms , on a car with over 200k. I only run 93 octane as long as ive had the car.

The problem-
Just after i let off the gas in certain load conditions (passing, going up steep hills , and any bogging) or if i blip the gas in 3rd 4th or 5th gear, my check engine light comes on and my the car falls flat on its face for about one second , followed by a large fire ball out of the tail pipe. The car goes back to normal running right after that.

My thoughts are that the ignition is cutting and causing unburnt fuel to build up and then explode out the back when it starts sparking again.
Any help with where to start ? Im replacing wires and coil for starters and cleaning important engine connectors and using dielectric grease

[jlevie]

My first suspect would be the CPS, followed by the DME, and then followed by the engine harness.

[oxymoron]

I cleaned off the cps and noticed something like a burn mark on the plastic part of the sensor . Im wondering if that is causing it. The sensor is only a year old but I had a problem with the wires over the summer. I'll ohm test that first

[oxymoron]

I went ahead and replaced the coil and wires. Seems to be running better but still rich. Poor fuel economy and also idle is surging a bit. I went ahead and adjusted the afm which im wishing I hadnt done.

[mazzo]

You should not mess with AFM because I believe they were calibrated so if you tweak it you may get good result at idle but worse result else where.