Current issue, the XJ idles very rough. When trying to accelerate it will not go past 3000 rpm (Probably some safety feature). Currently getting the p0300 code (misfire on multiple cylinders). Detects misfire on cylinders 1,2,3 and 6.

Recent changes, I changed my fuel injectors out and stupidly threw away the insulation surrounding the injectors (rail is still insulated). Replaced cps sensor with no change in problem.

Steps taken, I have pulled the plug on each injector one by one while vehicle is idling. Noticed a significant change on cylinders 3-6. Pulling injector plug on cylinder 1 and 2 had no effect (even both at same time). I have substantial fuel pressure (not sure exact amount but enough to spray me) and it retains psi even after sitting for awhile hot. I have checked for any vacuum leaks and found none. Injectors on 1 and 2 do appear to be working, you can feel them open and close. I have replaced all spark plugs with copper plugs and properly gapped them to spec.

My guesses, coil pack failure, bad wire somewhere or gremlins.

I will test the coil pack tomorrow. Any ideas or suggestions would be greatly appreciated!

-Thanks
Mike

 

Update
I pulled plugs and noticed cylinder #2 is very fouled and smelled of gas. The rest are a nice light brown color.
Further Testing
I tested the coil rail by installing a plug and using a jumper cable to ground the plug. Testing with this method created a strong spark on all 6 slots for the coil rail.
Results
The Jeep ran great for about a minute then the misfire gradually came back.
Changes
The Jeep is now able to rev past 3k rpm however it really does not like it.

My theory
Maybe the insulation on the coil rail boot is bad and it is arcing to the head instead of sparking at the plug.

 

Update #2
I have replaced the ignition coil due to suspicion of a bad secondary. Did not fix it. I have tested for compression and am getting 130-150 across all 6 cylinders. I have verified I am getting fuel.

At this point I am lost, I have fuel, spark and compression and yet it still doesn't run right. Any helpful advice or things I may have missed would be greatly appreciated.

 

Update #3 FIXED
After many many hours pulling my hair out I decided to go back to basics and treat the car as if it is the first time seeing it. Started simple, swap plugs and injectors to different cylinders and BAM, the issue moved. Found the injector was causing the issue because the NEW injectors I bought had one wrong size injector lol. I guess don't trust parts you buy off amazon. Jeep is now running like a top and all is well.....for now.

For those who are curious, the reason the spark plug was fouled is because the wrong injector was MASSIVE. I bet it was just dumping fuel in there