ProMod80

I have a 93 Formula with a nasty missfire in high RPM. It starts to break up around 4500RPM under acceleration. In nuetral it will rev to red line with no problem. I only breaks up under acceleration. I have replaced the coil,ICM,plugs,wires. If anyone has had similar problems please chim in. I'm pretty sure it's the Opti but i would think it would miss while just reving it and it doesn't. Any input would be great.
Thanks!

Spartan7

iTrader: (7)

I had the same issue. Rev all the way to 6000 just fine, broke up around 4500 under load. It was the opti cap.

ProMod80

what is it that goes bad with the opti and the cap? I have always heard of high RPM issues due to something going wrong in it.

Spartan7

iTrader: (7)

In order for the plug wires to be on the correct sides of the engine, small leads are run throughout the cap going from the pin on the inside to the plug on the left/right. When moisture soaks into the cap, it starts to arc these leads.

I'm not sure why it only did it under load for mine, but I had changed out everything else before that. Once I changed out the cap and rotor, it spun to 6200 under load with no miss.