964 running issue PLEASE HELP
 

I've got a friend with a 964 c4 that runs like crap when its cold. we can't seem to figure this one out. Once it warms up it seems to run fine but when its cold it will buck and stall like crazy. we have tried a cylinder head temp sensor. we found the belt broken in the distributor. i replaced that but it didnt get better. Has anyone out there experianced this kind of running situation?

Have you tested both coils and Ignition Control modules and made sure they start the car independently?

i will do that thanks

The reason I mention that was because my 964 was running bad/missing in cold and damp weather I eventually traced the problem to a bad ICM which was allowing the car to only run on one set of plugs.
You can remove the heater fan and access the coils and ICM easier, just unplug the units individually and see if the car will start and run on each circuit/distributor.

Have you checked the idle microswitch?

High Rev at Idle - Rennlist Discussion Forums

figured it out plug wires!

I just went through a similar ordeal but had new wires, caps, rotors, and coils. It turned out that my new wires were defective plus my air flow meter plug update was faulty. After fixing the plug and getting another set of new wires the problem seems to have gone away.

I just had the same thing! It was the plug wires! Boy did that cost me a bunch! But the cars runs great again!

Christopher