Bad miss.....Yes, I have searched....

Most of what I could find was either Renix, or the OP never came back and filled us in on what the issue was...

94 XJ 4.0 AX-15 172k on clock.

New exhaust...new cat and muffler, new O2 sensor, new TPS, cleaned the IAC, cleaned the entire TB. Tune up is 6 months old. New KPS, swapped out the distributor 6 months ago with a used. Fuel is good, and running freshly cleaned 703 injectors installed 5 months ago.

I am missing. Something bad at times, and gets worse as the Jeep warms up. I have also been noticing a rotary grinding noise, more like a high pitched metal on metal type noise that seems RMP dependent. NO CODES, NO CEL...reset ECM 1 week ago after replacing the O2 to clear codes and see if any new ones come back...notta.

Think it might be the distributor gears causing the miss AND the noise? Would I hear that?

Help...I want my power back....

Thanks!

Do a plug reading and a compression test.

Will do. I will post back results.

Beyond that, I do a preventative maintenance of a can of BG44k every 10k miles on every vehicle I own. It keeps the injectors clean and removes carbon.

You can test for a bad distributor by hooking up a timing light and watching it on the harmonic balancer. If it bounces around a lot, it is a sign of a bad distributor.

old_man said:

Beyond that, I do a preventative maintenance of a can of BG44k every 10k miles on every vehicle I own. It keeps the injectors clean and removes carbon.

Click to expand...

I use Seafoam...same concept?

Ended up being a few different problems at once confusing me.

Let's say this...I will not buy Bosch +2 plugs again. They were fried after 6 months...causing the miss. Not dirty, the electrodes were fried. The distributor was fine. I went back to Champion copper core.

The grinding sound it turns out, is the bearings of the alternator going bad. I oiled them, and they are fine for now.

Jeep is running well so far.