Bad coil?
#1
Rennlist Member
Thread Starter
Bad coil?
I'm having an issue with bad stumbling and misfiring under load. The car was running fine until a day ago. It mainly happens when pulling away from a stop, between 1k - 2k, and above 4K. It also doesn't idle smoothly, jumping a couple hundred RPM every couple seconds, though I'm not sure if this is related or if it needs a tune due to the full exhaust.
Couple things I tried:
Couple things I tried:
- Disconnecting O2 sensor didn't make a difference.
- Disconnected ignition modules. Car starts on primary but won't on secondary. Car keeps running if secondary is disconnected, dies if primary is disconnected.
- Thought it might be the distributor belt. Didn't want to strip the screws so tried an alternate test. Plugged the primary coil wire into the secondary distributor and left the secondary ignition unplugged. Car starts and idles fine. It seemed to idle smoother with no jumps.
#2
Sounds like your on the right track. Look into the 993 coil as a replacement. The replacement Bosch silver coils are known to fail. One of mine failed within 3 months of use!
pete
pete
#4
Rennlist Member
Thread Starter
Actually, it turned out to be an ignition module that went bad. Coils are still good. Surprised most of the people I talked to.