vitaminrust

hello folks, new member here. I own 2 XJs, an '88 and a '94. I have owned the '88 for a little over 3 yrs now. I have a problem that has been there since i bought it, and i can't figure it out. I am a mechanic, but not an expert by any means. This jeep has a throttle body 2.5 liter AMC 4 cyl which seems to be pretty solid....i drive it everyday. It won't rev more than about 3k, maybe 3,200 rpm. It pops,sputters and backfires. It has never gotten any better or worse, and it does this in any driving or climate conditions with no variations. It does it going down the road, or in park or neutral, hot or cold, damp or dry. I'm stumped......i went over all the obvious items first. So here is what is NOT wrong:
*cap/rotor/plugs/wires/coil/module/distributor
*crank sensor/throttle sensor/fuel injector/cat/muffler
*battery cables/major grounds/
*fuel filter/air filter
I can only believe it to be a spark problem, due to the fact that if i hold the throttle down, eventually i will smell raw gas, and then even cat conv.
other than this, the thing runs good for what it is, and i have had no other problems. This is very annoying, i can't let it kick-down or anything, so i look like a jerk merging onto the highway haha. Any help is greatly appreciated.

That Jeep Guy XJMJ

...**cough cough** sounds like its time for an I6 swap.....