I have an 83 CJ7 with a freshly rebuilt 4.2L/4.0L Head combo with less than 500 miles on it. It has a new distributor and O2 sensor since the rebuild and it has the earlier MPI kit installed. I'm using the cooler plugs as suggested by Hesco.


The problem is I have this funky smell coming from the exhaust or jeep and I find the engine missing at idle. The smell is bad enough for my apartment manager to ask me to use a different entry into the complex.

I pulled the plugs and they all have carbon on the "Base" of the plugs. The carbon is not on the Porcelain or electrode(s) but on some it's creeping up the ground electrode.

Is this engine running rich? How can I get rid of the funky smell? Could the Charcoal Canister be bad?

Thanks in advance