The (apparently) dreaded misfire

[Jeepn_Texas]

If I can't get it figured out I may take you up on the offer!

Cool!
It would be a good reason to take my wife to Wimberly for the day as well!

Something is floating in my head, have you checked to see if the distributor was installed correctly
at the right rotation I should say. try loosening the clamp and rotating your distributor housing a tiny bit,
just a degree or 2 (counter-clock wise) and then try starting it!
Check the wear on distributor drive by taking the cap off the top and rotating the shaft
back and forth to see how much play you have, should not be much.
You may be fighting a stretched cam chain this could throw it off enough to cause misfires,
If turning it 2-3 degrees counter-clockwise stops the misfire,
you should look into replacing the cam timing chain and gears!
How many miles are on the engine?
Let me know If it impacts the issue.
Have a great day!

 

[mots]

Does he have anything that would retard the engine to not get past certain rpm?
In my 06 i messed up timing while messing with OPDA, engine would run like OPs but power would be cut off to not get past ~2000ish rpm.
If so, that would be a good indicator of bad timing.

Yes, rotating the OPDA will alter the timing (either retard or advance depending on which way you turn it), but it isn't the proper way to alter\set the timing, as you found out. The timing is PCM controlled, but to run properly, the engine needs to be set to TDC by hand and calibrated in this position. At this point, the position of the camshaft sensor (i.e. OPDA housing position at that time) and crankshaft sensor are "indexed" by a special Chrysler scan tool. From then on, it knows the position it was set at and you only have a few degrees of freedom to spin the OPDA housing. If you spin the OPDA out of that position too far after it is calibrated, you will be out of sync and will pop a P0016 code (Camshaft Position A – Camshaft Position Correlation). This happens typically right as the engine reaches operating temp and you see the CEL come on. You wouldn't want to drive like this for sure and I'm sure the engine would go into limp mode if you tried to rev above 2000 RPM. That said, this is all applicable to the newer TJ's, not what the OP has.

On an older TJ, like his 97, rotating the distributor can do the same thing, but I'm not an expect on the older TJ and how the timing and PCM works with the distributor. I'd have to read up on it. On some cars I recall setting the timing by turning the distributor. For he OP, I do think properly calibrating\checking\setting the engine timing (whatever needs to be done on a 97 TJ) would be a good exercise if nothing else simple explains why the misfires are happening in all 6 cylinders.

 

[RMETeeJay]

It won't be from 97 to 04. It should be from 2000-2004, which won't apply to the OP. The 2000-2006 have an OPDA and direct ignition. The 05-06 OPDA are a bit different than 00-04. The 1997-1999 TJ's have a distributor that slides into side of the engine in the same spot. Both are geared to run off the camshaft in the same way.

But still, related to what you said, perhaps the engine timing is not set correctly and could potentially be causing a problem. Worth throwing into the bucket of things to consider.

Forgot that the earliest ones have distributors! If the cap, rotor and wires haven’t been replaced, I would do that and check timing.

 

[SCTexasTJ]

Hello all. I'm running the copper 985's. When I changed out the old plugs to these there was zero change in the quality of idle/misfire issue. I drove it some tonight. I can take it down the highway and run it past 4k, although you can feel it isn't right. Went by a shop tonight that was recommended to me. One of the guys said he had had a 2000 that basically did the same thing and said his ended up being his camshaft. My gut tells me this isn't mechanical just by how it runs in spite of the misfire, but by no means am I discounting the possibility. He also said it could be PCM. He wasn't "hard selling" me, just conversation since I have already tried so many things. I was about "this close" to ordering am OE crank sensor last night but didn't. They are quoting me 80 bucks to diagnose and this seems like a reasonable investment to maybe get some direction even though it's a blow to my manhood and I may lose my card!

 

[SCTexasTJ]

I did

Cool!
It would be a good reason to take my wife to Wimberly for the day as well!

Something is floating in my head, have you checked to see if the distributor was installed correctly
at the right rotation I should say. try loosening the clamp and rotating your distributor housing a tiny bit,
just a degree or 2 (counter-clock wise) and then try starting it!
Check the wear on distributor drive by taking the cap off the top and rotating the shaft
back and forth to see how much play you have, should not be much.
You may be fighting a stretched cam chain this could throw it off enough to cause misfires,
If turning it 2-3 degrees counter-clockwise stops the misfire,
you should look into replacing the cam timing chain and gears!
How many miles are on the engine?
Let me know If it impacts the issue.
Have a great day!

I did try moving the distributor slightly while it was running but there was no change in the way the engine ran. The odo says 207k but I have no idea if the engine really has those on it.

 

[SCTexasTJ]

Was reading through some threads tonight and found some talking about the clock spring creating issues with the TPS and causing idling and misfire problems. Curious what y'all might think. The horn on my jeep does not work and I'm assuming it's the spring but haven't gotten to that yet.

 

[eastbloc]

Worth a try man, at this point might as well

Considering how much i stress and overthink until i make something right,
if this was my issue, and after everything this was the solution, i would... simply ...