Ok heres the deal. I had a backfiring problem that I just fixed. I replaced the o2 sensor, distributor cap and rotor, fuel filter, ignition module, spark plugs and tightened up all my exhaust to eliminate leaks and the backfiring stop. I regained most of my power but the car is still not running right. Could this just be timing? or could my fuel pump be ****tin the bed? lemme know if this has happened to any of you guys. how can you tell if your fuel pump is going and how can you tell if you timing is off. I have a 91 305 tpi. thanks