10 CEL codes Ignition and misfire issues after highway drive

bagpiper22

Member
Joined
Feb 11, 2020
Messages
65
Location
Norwalk, CT
2001 TJ, 4.0 i6, automatic, 116k miles

Bought the jeep in February and have been working on it on weekends: changing all fluids, oils, etc. I've got a harsh stutter as it shifts from 1st to 2nd that I've been trying to solve. Only driven it around the neighborhood mostly to test various solutions to the stuttering, and no engine problems. Took it on the highway once for a few miles, got a flashing CEL but no change n performance. Checked at home and had a few misfire codes, but cleared them and they didn't come back (with just local driving).

Last weekend took a trip 30 minutes down the highway. CEL started flashing, then solid on, then flashing, but no change in performance. On the way back home took local roads (anticipating the need to stop), and jeep started bucking a little. Pulled into parking lot. Sat for a few minutes with engine off. Started again and ran fine, CEL still flashing then on solid. For a few miles at least, then more bucking, sluggish, no acceleration. Kept pulling over, turning off then on again. Would buy me a few miles, then get so bad I couldn't keep up with even local traffic (30mph).

Finally pulled into gas station and had AAA tow me home. Pulled these 10 codes:

P0300
P0301
P0302
P0303
P0304
P0305
P0306
P1391
P0351
P0352

Recently changed the plugs to AutoLite iridium XP, properly gapped. Previous owner told me the coil pack had been replaced.

Questions:
  1. Is it likely that one actual problem component is causing all the issues, or more likely multiple problems...if so, what's the best sequence to test to rule out each potential issue?
  2. Would a bad after market coilpack cause all these issues? How can I identify the maker of the coil pack I have now? I know the wrong brand of component can cause issues.
  3. Would a bad crankshaft or camshaft position sensor cause all these issues? What's the best way to test to see which is the issue, or better and easier to just replace both?
  4. As a possible solution to my stuttering, I have the TV knockdown cable tightened...could that cause any of my ignition issues?
  5. Anything else I should be checking that I missed?

Thanks in advance!
 
These DTCs are numerous cylinder misfires, Crankshaft and Cam Position sensor problems along with Coil Rail problems.
I would check the coil rail electrical connector for oxidation or if it's loose,
Then check the harness that is routed behind the valve cover that turns forward on the drivers side to see if it has chafes or bare wire caused by rubbing against a metal stud or valve cover.
 
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Been a few weeks since I could work on the jeep. I bench tested the coil with a multimeter and it was within specs (.8-.9) but it was a little warm in the garage.

Took her out yesterday for a short ride and began to lose power, chugging to a stop basically. Made it to the side of the road and turned off the engine, then on again. Ran much better, though not perfect, and made it home. Pulled codes 0351 and 0352 this time.

I'm happy to get a new mopar coil but is there anything else I should check before dropping $200?

Thanks!
 
My Jeep had similar issues. The iridium plugs didn’t work in my 01 and caused several random misfires as soon as I put them in. Went back to the autolite app985 dual platinums and several misfire codes cleared. My o2 codes cleared with the header replacement of the precats. I still had a cam and CPS code show up because I had replaced them While I was in there with box store sensors. I’ve had the Jeep 19 years so I was on round two of some maintenance items and should have known better to try to cheap out sensors lol. Stick with mopar sensors in the engine bay. The previous owner could have gotten an aftermarket coil rail so look for the mopar item number in it.
 
This site contains affiliate links for which Jeep Wrangler TJ Forum may be compensated.
https://www.factorychryslerparts.co...Crankshaft-Position/14909407/56027868AD.htmls this the proper sensor? 99 TJ 4.0 AT
Screenshot_20200822-132112_Chrome.jpg
link not working
 
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Sorry about that. It can be frustrating finding OEM for these older Jeeps. Good luck. Have heard mixed reviews on other brands but I think as parts get more rare you gotta try somthing.
 
@GEEP4ME thanks! Looks like an aftermarket coil. I’ll be replacing that after the crank sensor.

If anybody had a picture of a mopar coil showing the nunber, that would be great. I don’t suppose I missed it on mine but anything is possible.

Thanks!
 
My Jeep had similar issues. The iridium plugs didn’t work in my 01 and caused several random misfires as soon as I put them in. Went back to the autolite app985 dual platinums and several misfire codes cleared.
@Quigley interesting about the plugs. I recently put AutoLite iridium XP in. Maybe I'll switch them out for the double platinum.

Do you have a photo of the part number on your mopar coil? I want to see what the right one looks like. Thanks!
 
Looked at several, ok, a bunch, on ebay. Firewall/connector end of the coil, on the "side" of the coil, not the "top" with the coil bumps.

coil.jpg


Now you've got me curious as to what I have on mine.
 
So I finally got around to changing the crank sensor. I used NTK brand because I couldn't find a Mopar one anywhere. My thread on that whole ordeal here.

Happy to report no misfires or CELs, at least so far. Took her on a few short highway drives (2 exit trip) and so far so good.

I’ll get a Mopar coil if I need one.

Thanks!
 
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