car is backfire when driveing

[Firebird1]

Hi can anybody help me the locate and resolve the backfiring problem When I drive the car. I changed the lifters and smoother out the throttle body and install a new fuel filter and lines. the car ran fins until is missed shift and stalled the car. I then read on one of the forums that the coils could be bad so I changed all of them plus the O2 sensors. and the car idles fine but as i put it into gear it sluggish and backfire. I have change all that I know to except the spark plugs and wires. I'm thinking something maybe wrong with the computer. I don't have any diagnostics equipment. Can anybody help me resolve this problem? Is my engine ready to die? Thank you.

[Stealthee]

What year? If it is 91-93 the ECU could be at fault. You also need to check out the plugs and wires.

[Firebird1]

The problem was a bad PTU and the spark plugs. This was by trial and error method, I still need to change the plug wires.