So I have a 92 Laredo. The guy I bought it from completely rebuilt the 4.0 but never could get it running.

I changed some sensors but ultimately figured out it was the timing. I reset the timing to the marks 3 times and no luck. Came across a video where the guy cut the tab off the distributor where the hold down bolt went through so I could manually advance or retard the timing.

the rig fired up and ran great for a while. I noticed it gradually over time would develop a slight miss or jerk and became increasing harder to start. At first I thought fuel related and changed the pump. Things seemed fine for a few days and the issue came back. I seemed to go in circles checking everything, sensors, grounds and so on.

my issue I have found is that it is slightly slipping out of time for whatever reason. It does not matter how hard I crank down the hold down bolt it keeps happening. I can loosen the hold down bolt slightly rotate the distributor and it will fire right up and run perfect for a few days or weeks then it starts all over.
does anyone have any suggestions or input on how I can get this to stop?

Thought about setting time and then welding the hold down tab to the distributor itself. Do I have another issue, timing chains or something else? It’s getting super annoying because it seems to always happen at the most inconvenient times. When it’s dialed in it runs and drives better than any of the other 5 xj’s I’ve owned.

 

could it be the ignition pickup coil sensor in the distributor cap? A lot of people also call it a cam sensor but you can't find it always by that at the auto stores.

 

unfortunately I have replaced the whole distributor set up.
I actually decided to post this to chat gpt just to see what it said and learned that it could possibly be the CPS not sending a consistent signal. It will work fine for a while and when I turn the distributor it only adjusts the injector firing not the actual timing.. I did replace the cps with the Autozone version and chat gpt to my surprise said that use mopar or nothing. That all others are inferior and can cause my exact issues. Guess I’ll order one and post my findings!