my 89 lo3 has a missfire and i cant figure it out. i have good compression and my cap, rotor, coil, plug wires, and plugs are new also has new fuel pump. when it idles it aint too bad but when you put a load on it like power braking it misse violantly. is there other sensors that can be causing this? im not too good with fuel injection so i could really use some input. thank you

 

Look for a rusty pick up coil in the distributor.

 

it looks a little corroded, but if that was bad would it still be able to run.

 

Could also be timing. Not sure on that car how the timing is controlled, probably via computer, but it's worth checking your initial and see if you accidentally tweaked the distributor.