Getting very frustrated!!!!

OK, i got the 87 cherokee running very well, even got it smoking a lot less, as my earlier post. EGR valve was bad, replaced with a working one. Coil tested not like a new one, replaced with one, not new, with one that tested higher. One of those made it run phenominal! While driving it, it didnt stall run at 750-800 idle, and it really only puffed out at when changing gears.

Ok now the problem, it stalled when coming to a stop, and it took a few cranks to start it back up. When I got it back up i had to double foot it back home. When I got it there it would stay at idle, it sounded like it was misfiring, and sounded like it had a severe leak, cant really tell if its intake or exhaust. My vacuum went from being just perfect at 15-16 to right around 9-10.

I went inside disgusted, and decided to look at a few more things. When I went to try and start it, it took forever to start at least 10-15 cranks, when it did finally start it revved right around 2500. I unhook the TPS, the idle drops and then dies, even if i connected it back.

List of things done before the problem:
New-CPS, cap, rotor, plugs, wires, fuel filter, valve stem seals
cleaned throttle body, IAC, and seafoamed
Fuel pressure 32 with vac 39 w/o vacuum
comp 145-155
vac 15-16
engine is 4.0 renix 234,xxx

I am thinking either dist jumped out of timing(if at all possible), and maybe the cat(not the kind that meows)

Please any help would be nice and very appreciated, Im about to throw in the towel!

Seen several distributor gear pins fail lately. It's an easy check, pop the distributor cap and twist the rotor back and forth. It should only have a couple degrees of play.

Its just so frustrating you get it running pretty much the way you want it, and then it kicks you in the nuts. Ill give that a check in the morning, thank you JJacobs

Any other thoughts to check? Im gonna check the O2 sensor and the cat. If it starts up just fine when its cold, that somewhat narrows some stuff down.

The high idle makes me think vacuum leak. Items to check:

vacuum booster leak
TB to manifold leak
intake to head leak
bad IAC
bad TPS
Bad MAP or leak in line to MAP (if Renix, check plug in side of TB is the right orientation)

A can of brake cleaner sprayed CAREFULLY will show up a leak asap.

I'm chasing a similar gremlin now..... kinda.

Mine got to a point as to it would start at random. Once when that happened, I had a spark tester on one of the plugs and noticed I was getting no fire.
My problem in that case just happen to be the shielded wire running in the loom (plastic loom protector was missing) from the firewall to the front of the engine down to the Knock Sensor.

The wire was shorting on the top of the head, at the front of the engine. Fixing that stopped my stalling issue.
Just a thought for something to look for ............

I guess its just wierd how all of a sudden it started to happen, but it almost feels tming based. Its giving me the same effect as if I took some spark plugs out. But I still have a few stuff to test. I do have another TPS that Ill give a shot, and Im gonna put on the old coil. It possibly could be a grounding issue, but thats a given.

Ill keep you guys posted on what I find, thanks a bunch.

Generally, I have found a "hunting" idle to be TPS related.

You are looking for a steady 700-750 rpm idle in DRIVE, with the engine and transmission both warmed up, about 20 minutes of operation.

Thats what I figured that maybe the TPS was on its way out anyway, Ill try the other one I have. Who knows, Ill just go through and test everything again, thanks again.

OK, well I changed back to my original coil and put on the other TPS, it drives just fine now. It does seem to hunt for an idle, but it stays around 750-800 while in drive and after 20 min of driving. The smoking does seem to have diminished, but it does seem to give a good puff of smoke at start up and it does take a few cranks to start up. nothing a set of new spark plugs might help out, and a new O2 sensor.

My 4WD is now in my list, it does not have any of the hoses in the engine bay, I wonder if the owner before capped it off. I can put it in 4hi but it gives me problems and 4lo is definitely a no-go. So I guess I just need to get the whole vacuum lines for the transfer case.
Thanks again for our guys help.

Ok, now a new problem, when the jeep is cold, you start it up it revs to 2000 rpms and when you try and drive it, from a dead stop you press the throttle, it bogs down and dies. I am somewhat thinking TPS? Any other ideas?

Was the "new" TPS actually new and from the dealer? I've found that with the Renix system Dealer TPS's are better and still inexpensive. Did you adjust the TPS when you installed it? Also, throw that new coil back on. I try one thing at a time that way you can narrow things down.

Well, no, the coil and tps was still used, I just wanted to try a different one. The TPS is the different one, and I think it has a dead spot, no not properly adjusted, why Im leaning toward the TPS. Coil could have been ok, Ill just change just the coil out and give it a shot, but "my" old one was just find, I was just thinking it may have given a weak spark causing it to run rich, finding out its more along the lines of I have a lot of crap still in my system that needs to get out.

I think a brand new TPS is much needed and the coil is gonna stay the same with the spare kept with the jeep. Gonna go through and retest all the sensors, maybe the MAT is actually everything to blame, or at least a huge contributer. Ill keep you posted 88, thank you.

Try and adjust the "newish" TPS. Just search here or on Google for Cherokee Renix TPS adjustment. You need a decent volt/ohmeter but can be done at home.