Probably gonna be a huge waste of time. I've never seen that happen on a 4.0.

 

Ok well might rethink that one.

 

Look inside your distributor and check for shaft play. I still don't like the compression readings though.

 

how many miles on your motor? did you check the c 101 connector?

 

211,000 whats the c101 connector ? I did check the blinker fluid if thats where this is going. Lol

 

Here's the procedure for the c101 connector. Needs to be done regardless. It was a source of many problems as explained below.

Renix Jeep C101 Connector Refreshing
　
The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before.

Almost every critical signal between the engine sensors, injectors, and the ECU travel the path through the C101.
The C101 is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time.
Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth.
If you have a small pick or dental tool tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter. Apply a true dielectric grease, not the stuff that came with your brake pads, to the connection and bolt it back together.
　
　
Revised 11-29-2011

 

I will clean that tomorrow. Could the misfire be caused by a bad fuel injector?

 

Of course it could, or it could be a crappy connection to an injector. Inspect your harness where it passes near #5 and #6 injector. Is it rubbed through?

But, always do the ground refreshing no matter what. It is critical to eliminate the grounds as a source of your issues.

 

Update: running GREAT! You should defiantly add pulling the injectors and replacing the o rings and cleaning the injectors out to the list. This was really a 5 dollar fix. We got the o ring kit at Advanced for 4 and some change plus a little carb cleaner.
We took the injectors and cleaned all the carbon off of them and then using carb cleaner sprayed the top of the injector and applied 12v to them.
This opened the injector and allowed the cleaner to flow through the body of the injector. DO NOT DO THIS DRY! It will fry the electronics.

 

Glad you got it going. For future reference, keep an eye on those injectors. They tend to leak gas externally at a crimp, causing gas to spray on the exhaust manifold.

My suggestion to people with older Renix Jeeps is to contact www.precisionautoinjectors.com and get a set of 6 injectors, flow-matched, four disc design, with new o-rings delivered to your door for about $100.