86 951 Driver

I can feel the car misfiring a little bit. What could it be? There are no arcs from the wires or anything like that. Here is what is weird about it, it only misfires at higher rpms. THen after running it hard it makes a popping noise kinda like raw gas igniting in the exhaust. Anyone in STL who could help me look at the car and diagnose the problems? Also can the tranmission mounts on the 924S go bad and causing jerking? It jerks back and forth when getting on the gas and letting off.

Micah

The misfire could be a few things - when is the last time you replaced the cap/rotor?

The jerking you're describing is a tell-tale sign of clutch failure

Micah

Chris_924s

How do you know it's not the plug wires arcing to the hood at higher RPM's? Do you have a underside hood insulator?

86 951 Driver

I don't know for sure if the wires aren't leaking sparks at high rpm's but wouldn't they leak out at idle if it did at higher rpms. There is underhood insulation. I was wondering if I could just change the cap and see if that makes a difference then change the rotor if it makes no difference.

DanG

Check your plugs. Specifically the gaps.

The spec is .028-.030"

New, properly gapped plugs transformed my coughing/gagging engine into a perfect runner. I had the same symptoms you describe.