1992 Jeep Cherokee 4.0L, 6 cyl. idle question:?

That Jeep is 18 years old. The radiator could simply need to be replaced (the fins inside eventually will clog and become very inefficient) As for your idle problem, have you checked the fuel pressure? Again, on an 18 year old Jeep, The fuel injectors could be faulty, your fuel filter could be clogged and your fuel pump could also be on the brink. I own a 92 Cherokee myself she's got 280,000+ miles on her!!

Jeep Cherokee 1992

I own a 89 4.0L 4wheel drive with 200,000 miles. Been there-- done that. My bad idle turned out to be one bad fuel injector.

A worn out water pump or older radiator hose or blocked hose can cause overheating.

Even junk/rust inside the radiator can be blocking the fluid flow.

Overheating just one time in the past can cause a leaking head gasket or cracked block (or cylinder head) which can lead to allowing antifreez or water into a cyclinder causing misfires and rough idle.

Usually this results in low radiator fluid and in some cases 'steam' or white smoke out the tail pipe especially when first started up after being parked over night.

A good radiator shop might be able to help find it..

I assume you have ruled out a dragging emergency/parking brake that was set but then failed to release fully, and improper engine timing?

Good luck.

Thinking outside the box can help with any older vehicle.

I even considered buying another 89' that ran decident but had some body damage just so I had cheap parts and something to experiment on.

TJ

92 Jeep Cherokee Laredo

Does it use/lose any coolant? Any white smoke from the exhaust? If it overheats and idles rough at the same time, it could be because of coolant loss to a combustion chamber, i.e. cracked head, blown head gasket. If that's the case, a block tester would be able to tell, or tell-tale signs of coolant burn on a spark plug. Otherwise, these are probably two different problems. Good luck.

Does it really overheat? Like get hot enough to blow out steam and hot coolant into the radiator overflow bottle and onto the ground? If so, it very well could be a bad head gasket. That too would explain the rough running.

Have a compression check done to it, or if you know how to do it, do it yourself. That is the easiest way and quickest way to know what is going on.

Best of luck to you with it,

Gordon.

The first thing that I would check was if you have water in your oil. The oil will look like chocolate milk if this is the case. If you don't, check to see if you have oil in your coolant. Either of these is a sure sign that you either have a blown head gasket, cracked block or head, or blown intake manifold gasket. All of these problems will make it run rough and overheat.

You engine is overheating maybe because the outside of the radiator is full of bugs and dirt. Go to a Do It Yourself car wash remove the fan housing to expose the radiator and pressur wash the crap off the front so air can flow through. this is what cools the antifreeze.

Good Luck !!

Take it to a reputable shop and have it analyzed. You are spending money on parts and guessing.

You could have had it running correctly by now.

Try your O2 sensors.