Hey all,
I have a 1991 GTA Trans Am with a TPI. A few days ago, it started bucking and backfiring and lacked power when steping on the gas, which caused it to buck and backfire even more. Now, to let you know, i´m in Germany right now with the Air Force and I just picked up the car from the port here about 2 weeks ago. While I was driving it to the port back in the States to have it shipped here, it started doing the same thing. My friend who was my ride back said it was probably the coil we put in. It was an aftermarket one made by Accel. Luckily I had the stock one in my trunk, so we just swapped the coil out right there on the side of the highway. The rest of the was to the port, it was fine.....drove like it should. When I picked it up from the port here in Germany, it was fine until a week later when it started doing this same thing again. I figured now the stock coil went bad too. Now it seems like the problem has been getting worse. Its been sitting in my shop parking lot for the past 3 days. It won´t even start now. I swapped out the coils again and again trying to start it, wont start....someone gave me a spare coil they had....wont start. Now im thinking its more than the coil. Took off the cap and rotor, they seem fine. Wires seem fine. Havent gotten a chance to pull the plugs.....you all know how much of a pain they are to get to. They should be fine though anyway. The engine was just rebuilt and they changed most of the basic ignition parts. Could it be the module?? What else could it be? Also, when I was still able to start the car, and i would rev the engine it would run rough obviously and I was noticing black soot coming out of the exhaust pipe onto the pavement. So, something must not be burning right. I´m not sure if this would be something as well, but the day after I picked it up I put a new 52mm throttle body on. It had a slight idle problem, but quickly went away after driving it for a few minutes. This new problem has got to be something totally different. Im still pretty much in the learning stage of auto mechanics, but would a fault in the ignition system cause the car to run extremely rough, backfire, and cause soot to come out of the exhaust pipe?? And now not even start. Seems like as the days went on it just got worse.....and it sucks cause many parts I can´t get here in Germany for that car. They have to be ordered.....please help me out guys!! Thanks in advance.

 

Get a fuel pressure gauge and check your fuel pressure, this sounds more like a dying fuel pump than an ignition problem.

 

Welcome Aboard!

Or, in your case, would that be "abroad?"

Isolate the problem. Testing the fuel pressure would help, as Kev indicates. You might also check for spark as an assistant cranks the engine. One of those should get you working toward the real problem.