Bluebyu

Tried searching around but still no answer. Truck runs fine , drives smooth, will never stall but has a rough idle. No codes are in the computer and I have replaced a bunch of things that sorted out other issues but none with the idle.

I have changed...
Spark plugs, distributor cap, fuel pump, air filter, primary and rear o2, and I have cleaned the throttle body thoroughly.

Oil is at a good level and clean, truck has new coolant and thermostat in it and my fuel pressure is good too.. where else do I go to solve this rough idle? I'm thinking my next move is to try a new ignition coil. What do you think?

CCKen

Are you hearing any valve train noise...ticking, knocking?

Have you checked to see if each fuel injector is "Clicking" while the engine is running? Best to use a $10 stethoscope from O'reiily's to listen to each injector.

You can pull each injector connector off (in turn) while the engine is running and see if the engine stumbles with the connector removed. The #3 injector connector is a PITA to get off so you may need to remove the throttle/cruise control/transmission cable bracket to get at it.

Muaddib420

Could be your idle air controller. My idle is also rough/low. I may try to buy an IAC from the parts store this weekend and swap it out to see if there's any improvement. I ordered one from flea bay for $15 but got sent a wrong size. The ones at auto store run $70.

letsgomuddin

A good throttle body cleaning goes along way to improve idle quality. That said tho, most XJ's and other Jeeps have a slightly rough idle due to the crappy single hole fuel injectors they use. One of the best ways to improve idle quality is to swap them for 4 hole Neon or Ford injectors. More info on this swap can be found with the search function.

Bluebyu

did this, when I pull an injector the engine seems to stumble more then it does with them plugged it. It seemed about the same on all the pulls.

How about spark issues? Maybe a not strong enough spark in a cylinder.. I believe this problem is in the ignition system but I could be wrong.

this is exactly what mine does. (not my video though)

Roler

Rough idle, but otherwise no running issues.
Check (by cleaning) your IAC, as has been mentioned. This controls the air intake during idle, and over time, might get glogged up, therefore not letting the engine idle correclty. Remove, clean and refit.
Be gentle with the 'rod' that moves in and out, not to bend it.
See how you go and let us know.

Ian96XJ

+1 IAC

But people almost always say Seafoaming the engine smooths the idle out, too. Wouldn't hurt to try and only about $8. So clean your IAC first and if that doesn't work, try Seafoam, then maybe upgrade injectors.