I have a 96 Cherokee Sport with a 4.0l from a 98 in it. No CEL. Under 50k on the odo and have been experiencing the good old bucking during light acceleration. It idles perfect and I am only experiencing this "buck" while my foot is barely on the pedal. The Jeep is kind of a weekend toy so it doesn't get driven daily, but this problem is very intermittent and some days it won't happen at all. Others.. it does it A LOT! I can leave it idle for days and it will not misfire or "buck" once. If I run it hard at WOT it pulls strong and I have never experienced the buck either so I am really at a loss because most of the problems I see with this it is happening during WOT, at idle, and the Jeep is stalling all together at times. None of these have ever been an issue. I have done a full tune up, plugs, wires, etc.. I have replaced the fuel filter / pump and I had the o2's replaced approx 6 months ago. Ideas on where I can start troubleshooting this? I don't want to dump a bunch of money on replacing sensors that have nothing wrong with them so is there a way I can actually test them on my own without a obd scanner? I am an electrician so I have a multimeter / clamp meter and tools but just need to be pointed in the right direction to start pulling stuff apart and checking it. I have physically checked all the wires / insulation that I can get to and things seem normal. Any help would be greatly appreciated! Sorry for the long post but thanks for reading!

 

Another thing I forgot to mention is that this "buck" is a one and done sorta thing.. It doesn't do it over and over again. It has never done it more than once at a time. I actually think I should call it a hiccup instead of a buck. That's another thing that kind of has me baffled as most of the people with this problem that I have seen it happens 5-6 times as they are trying to run through a gear. Mine is accelerate... accelerate... accelerate.. buck.. accelerate... accelerate.. Hope that makes sense :P

I also have pretty much narrowed it down to only happening between 2-3k RPM. If I keep it high in the revs, it might still happen on occasion, but it is pretty rare. Seems to be a low rev, low acceleration problem..

 

Sloppy throttle shaft or defective TPS.