4.0l engine check engine light

[cjkarl]

I have a random miss-fire alarm- p301,2,3,4,5,6 and can't get the problem fixed. Done all the regular stuff, new cap,rotor, plugs,wires,crank position sensor, checked all wires and connections still get check engine light????? '99 Wrangler TJ 4.0l
Any Ideas?
Karl

[inVERt'D]

I'm cornfuzed--you have a cap and rotor, and a CPS? Is this a troll?

Clear the codes/ CEL.

[CharlesS]

If he isn't a TROLL... then I would suggest checking the coil(s).

[6spdYJ]

The cap and rotor do the same old job. The CPS is what controlls the crankshaft/ignition timing. The distributor hall effect transmitter controlls the injector cycle start.

[cjkarl]

What do you mean by troll? I'am not the village Idiot and cannot figure this out. This engine only has 1 ( one ) coil and changing parts is o.k. if you don't understand what the problem is, have more money than brains or don't understand how to fix a problem.

[NakedJeeper]

I've been there - having replaced everything except the coil and still had random missfires myself. A new coil fixed my problem.

I'll bet the oem coil is still bolted to the side of your engine. They should last 100k miles or so. I got about 200k out of mine.

[dirtman13]

Don't mind the troll comment. The testosterone levels have been a little overloaded lately.

Being that your misfire is hitting all cylinders I would tend to agree with the coil being a possible issue. Make sure you check the voltage and ground going to it first before replacing it.

If your CPS was bad you would get a separate code for that.

[inVERt'D]

What do you mean by troll? I'am not the village Idiot and cannot figure this out. This engine only has 1 ( one ) coil and changing parts is o.k. if you don't understand what the problem is, have more money than brains or don't understand how to fix a problem.

By "troll" I meant a post intended to start a confused, stupid argument, like you would find in the "Political Discussions" forum. I said it tongue-in-cheek; no offense taken, I hope. And dirtman13, I have very low testosterone, thank you very much! :homer:

I think your last sentence means you'd rather avoid spending more money than necessary? Well, that's why I suggested clearing the codes and CEL to see if any of that stuff you already replaced had any effect. I also wasn't assuming that you could hear or feel the miss. FWIW, a I've had loose ground wire on a coil cause some serious missing.

[brokenujoint]

I have very low testosterone, thank you very much!

Probably explains the boobies....

[inVERt'D]

Are they really noticeable!?

[cjkarl]

Found Chysler paper on random m/

No offense taken by other posts at all! I have found a lot of you from MJR the trail and and you all are there for the trails and Jeeps/people. Never heard of a troll!!! Have a paper from Jeep that says problem might be caused by carbon build-up on exhaust valves and causing them to close slower than normal. Valves may not be rotating and causing the dtc's. ! Just a lot of frustration on a flashing cel. Also says by checking exhaust valve ends under rocker tips you can tell if valves are being rotated or not . Will pull valve cover off and check rockers where they meet valve tip. I f it is rotating it will look like a bulls eye, If not in will have a line across the end. Will keep up to date as it may help the next guy. BTW this is my 17th jeep and still have the first '50 willys pick-up and 3rd jeep CJ-5 ( for sale ), HAD THEM ALL!!
Will take off cover and keep updated. Can't feel a darn thing when driving THANKS really!! Still not the village idiot!!!!

[cjkarl]

tj missfire

Finished TSB paper. Had to decarbonize combustion chamber and exhaust valves. Jeep wouldn't sell me the can off stuff they use, they wanted 2.7 hrs. to remove valve cover and bridge and rocker assy. to check that valves are rotating, No problems there. So went to NAPA and got a can off SEA-FOAM. Ran it thru per TSB and no more CEL. Runs a bit better also.

[inVERt'D]

So it's reporting misfires, but what's really happening is predetonation. That's good to know! I was thinking of trying that SeaFoam stuff myself. I know it's not as good as the professional stuff, but sounds like it must work pretty good.

[cjkarl]

engine missfires

Still gets CEL May have to get Toyota and get rid of this POS

[NakedJeeper]

Did ya try replacing the coil?