Novak Conversions Jeep Wrangler TJ engine mounts

98 TJ 4.0 intermittent misfire, no codes

gcamp12

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Original poster
Joined
Aug 4, 2024
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1
Location
United States
I'll be driving along with the engine hot and it misfires under steady throttle causing the whole car to jolt. The tach needle drops a few hundred and then shoots right back but there are never any codes.

This problem has been happening over the past couple of years, it'll misfire here and there, I'll replace something and it seems to clear up but then comes back a few months later.

I've already tried new plugs, wires, cap and coil, catalytic converter, both O2 sensors. After the most recent round of misfires I ran a fuel pressure test, it idles normally but loses pressure faster than normal after turning off ignition. I'm considering a new fuel pump because of that, but I'm wondering what else it could be.

Any other ideas? Thanks!
 
I'll be driving along with the engine hot and it misfires under steady throttle causing the whole car to jolt. The tach needle drops a few hundred and then shoots right back but there are never any codes.

This problem has been happening over the past couple of years, it'll misfire here and there, I'll replace something and it seems to clear up but then comes back a few months later.

I've already tried new plugs, wires, cap and coil, catalytic converter, both O2 sensors. After the most recent round of misfires I ran a fuel pressure test, it idles normally but loses pressure faster than normal after turning off ignition. I'm considering a new fuel pump because of that, but I'm wondering what else it could be.

Any other ideas? Thanks!

Hi....did you ever get it resolved...I'm in the same predicament. I replaced everything to include fuel pump. If I really feather the accelerator the misfires are not as bad. Going to replace the PCM next. Seems like the fuel/air mixture is wonky during acceleration.
 
Novak Conversions Jeep Wrangler TJ engine mounts