Could the wrong firing order cause a Pontiac Fiero to run rough and not accelerate?

Answer 1

timingWrong firing order would probably make it so it wont even start, the timing could be off though. Most likely, you will need to change the MAP sensor and accompanying vacuum hose.

I just went through 4 months of troubleshooting and replacing a lot of parts on my 86 fiero SE 2.8 L. After replacing my fuel pump, fuel filters, fuel pump relay, air cleaner, distributor cap and rotor, and finally the ignition control module (the reason my car woulnt start at all), it finally started. However, it ran really bad. It sounded like I had a horrible exhaust leak or that my catalytic convertor was bad. It would pop, had no power at all, going uphill was impossible, it would overheat (which never happened believe it or not) and it wouldn't idle smoothly at all. It turned out that it was the firing order. Once that was fixed, my timing was fine and my car is running better than it ever has.