Update: it was a bad ground.

I used my laser thermometer to measure the temp of the exhaust manifold trying to find the dead cylinder. Cyl #4 was half the temp as the others so I unplugged the #4 wire from the distributor and the engine ran exactly the same. Before pulling spark plugs out, I took my spark tester and plugged it into cyl #6 ( to be methodical), and now the car was running good. As I was unplugging the tester and found burn marks on the plug wire. The ground cable was rubbing against the wire. So I electrical taped everything and rerouted the ground wire.


Autocross on Saturday, misfire on Monday.

Felt like 5 cylinders this morning, lots of vibration. Surging idle. Rough revving up in neutral. Runs correctly under acceleration. Stutters when trying to maintain constant speed. Occasional backfiring.

I’ll have to wait till after work to try diagnosing the problem.

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