My 92 camaro rs with a 305 TBI runs for about 5 seconds with contins backfires. Every time I replace something the problem gets worse. I put the old parts in it and it still doesn't get any better. The computer is setting the timing well past 10 deg. BTDC at idle and the exaust smells like I'm burning alcohol instead of gas (which gas is in it of course)would a bad MAP sensor be causing this? Also I replaced the TPS today and I'm still reading 5.02v across the connector to the TPS. What causes that? I've tried testing my MAP sensor by just unplugging it and the car stumbles for a few seconds and stalls. I also tried adjusting my minimum idle but the car wouldn't even run with the IAC unplugged. The last two problems were how the car was acting before the constant backfire condition I have now. Please help I desperately need to get this car running and stop raising the hood on it every day.

 

Have you pulled the plug wires 1 at a time and checked for a miss?

 

I've attached a timing light to each wire to check for misses before the car started to do what it does now and there was a steady blink from the timing light on every cylinder. Now the car doesn't run long enough to check anything unless I'm holding the pedal down to the floor maxing out at a whopping 1500 rpm. Once I let off the gas the car dies.