Engine missing, backfire, occasionally

ZCar

New member
cj5 owners, or everyone... question

New to the forum but owned jeeps since 1947.

I currently have 3 (2002, 1994, and 1990).

The 1990 is giving me some problem. Sometimes (50-60% of the time) when I am driving under an acceleration or load situation it starts to backfire and sputter. If I floor the accelerator it will pick up speed just fine but if I am gentle on the throttle it coughs, spits, and backfires. It starts good (with a little grinding) and runs good at idle.

I checked the plugs, regapped them and drove about 500 miles. Plugs were power white. Additionally I am getting about 18 miles to the gallon mixed city/highway driving so I believe if anything I am running lean.

I replaced the fuel filter, plug wires, plugs, distributor cap, and rotor without fixing the problem.

So now I am looking for suggestions on how to proceed to alleviate the problem.

Your thoughts, ideas, or just comments would be appreciated.

OH. I also have a 1990 300ZX TT that has been highly modified that is why the ACar e-mail address.

Thanks
 

Do you have any air leaks around the manifold gasket and at the carb seat that might be causeing this. And by the way welcome to the board. tug
 
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