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Old 06-20-2011, 11:21 AM   #1
Join Date: Mar 2011
Posts: 12
Misfiring... Reposted With Better Information, Please Help!!!

My Jeep is a 2002 Wrangler X, (4.0L 6 Cylinder) with about 76,000 miles on it. It's been throwing misfire codes (all of them, each cylinder and random misfires) since March of this year.

Replaced a Oil Pressure Sending Unit a few months ago when the oil gauge went haywire... ripped a wire, spliced and replaced it... no problems.

Few weeks later, check engine light come on, engine dies... open the hood and the Crankcase Vent tube is laying on the crankcase... replace it, and the Crank Position Sensor (as indicated by the OBD) the first one was "bad" it too was replaced... After a few dozen miles, the misfire codes came back again.

Replaced the coil, plugs (regular Champion plugs)... It was time anyway... Check engine light still coming on after about 100 miles and if it gets over 65 mph or 3000 rpm....
The jeep would lurch and lose power at speed, definitely felt it misfiring...

Replaced the ECM, a mechanic I trust said it was bad... Engine Light still came on after about 100 miles and over 65 mph/ 3000 rpm...

Replaced the valve springs.... the engine felt and sounded great when I got it back... light just came on after, you guessed it about 100 miles and over 65 mph... Still feels and sounds great.... but the engine light reappeared again...

Replaced the Cam Position Sensor last week... More or less because it was easy and cheap it felt like I was doing something, but to no avail, after a few miles at highway speeds.. it was back...

It no longer feels like it is misfiring, as it did before the Valve Spring and ECM replacement... Bought an O2 sensor, got under the jeep and then realized there were three more of them...

I am at a loss... wondering if it's a shorting wire? Can't figure out why it doesn't "feel" like it's misfiring, but still throws the codes at a predictable interval... would love to hear ideas before I go buy three more O2 sensors... What have I missed Jerry Bransford????

Also... Are there "plug wires" that can be checked on an engine that uses a coil pack?? I have gotten lots of free advice that suggested plug wires... but that seems to be the whole point of a coil pack...

Bought some double platinum Champion plugs, but haven't put them on yet... Both me and my mechanic are stumped...


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Old 06-20-2011, 01:12 PM   #2

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Wow. Hope u get an answer
2007 Rubicon/Rock Krawler triple rate 2.5" coils/RK rear TB w/ a teraflex raised bracket/Rancho 9000 31/32XL shocks/Synergy flipped draglink,ball joints,tie rod /Hankook MT 315-75-16 on Level 8 ZX's/Rancho geo brackets/Ruff stuff uppers/Fox ATS stabilizer/Adams front DS/Artec front armor w/ Currie upper bushings/Rancho cat back exhaust.

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engine light , misfire , sensor , valve

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