I think I might have had that problem too when my Jeep ran. I was driving it around the yard in 4LO and when I'd go over a bump I'd notice that. I always just thought it was the Jeep rocking and my loose seat moving back and forth, but maybe not. I'd be interested to see what the solution is, and if it contributed to my potential tranny/tcase failure.

 

yeah! mine does it when i go over an alright sized bump or hole in the road. like it rocks or its not getting gas you know?

 

Do you have a CEL on? Could be the throttle position sensor, sounds kinda like what mine was doing. Bought a new TPS for less than $30 and fixed the problem. Takes 5 minutes to install. Mine would stop doing it when I got back on the gas though, but a bad TPS can act wierd.

 

Sounds to me like its not getting enough fuel over 2500 RPM. How is your fuel filter? What about the pump?

 

yeah! mine does it when i go over an alright sized bump or hole in the road. like it rocks or its not getting gas you know?

Well turns out my issue isn't tranny related but the bucking is still unknown. It's exactly like it's losing gas and then surging an then dying and surging. I'll have to see if putting the clutch in stops it. Problem is, it throws me outta my seat haha. Idk about you, but my fuel filter looks ancient, could contribute. Also, when I hold the engine around 2000 rpm, it'll run steady, then bog down to about 1500, then come back up. Over and over.

 

how long have you been driving stick.......

keep in mind the YJ is a bumpy ride, so maybe your not giving sustained pressure on the gas pedal and you yourself are causing the bucking, i used to do the same thing when i started driving stick

 

Yeah I agree^^^. I did that when I first started driving stick. You are not giving it enough gas to keep it going. Plus not an even amount of pressure. Also when you hit a bump your foot will move and cause that issue, low gears usually. Jeep, you gotta keep a steady foot.

 

This could be a possibility. Try anchoring your heel on the floorboard when you drive. I had this problem with a few of my tractors.

 

i always found the method of digging my foot into the transmission tunnel. i almost positive that THIS is the problem

 

For me, I wouldn't be surprised. Not that I'm an extreme amateur at driving stick, but I'm not a pro. I'd say I'm pretty good, but as you said, Jeep is a bumpy ride and my yard is bumpy as anything so that could be it. I do anchor my heel to the floor though. We'll see how it is on the road here hopefully soon. The OP it sounds like is having a different problem. Something else that might contribute to it is the engine seems to bog down around 2000 rpm. Only for a second or two, goes down to about 1500, then comes right back. The surge back might cause the Jeep to jump forwards starting the bucking routine.

 

I plan to add another spring to my throttle as I find the YJ throttle to be too light and hard to control on bumpy terrain, of course a hand throttle might be in order too. If this is in fact a mechanical problem my money is still on a TPS or a fuel delivery problem. Mine acted just like this and I put in a new TPS and she smoothed right out!

 

I've been driving stick for around 2 years i know it's not that. ( not to be concided(sp?). but the fuel lines/filter/pump seems to be something that need to be checked out. after reading the "new to stick" comments i tried the advice but that only made it worse. i know the yj is a rough ride plus i have a body lift on it (not my decision lol). before i posted this it stopped doing it so who knows. thanks for the help im having the fuel pump and filter checked soon.

 

Check your motor mounts.