Jerking at 2-2200RPM

hey guys my tj 2.5 has a problem strictly at 2-2.2k RPM in any gear staying steady at that RPM my jeep is jerking back and fourth violently. when i push the accelerator to the floor the problem stops same when i let go. i just put a new engine in it (a new 2.5). this engine idles perfect. its quiet. when i put in the new engine it got a new distributer cap, plugs, and wires. So im kinda lost any ideas?
 

Re: Engine Dying and Jerking

alright tomorrow ill try that and ill let yall know how it worked
 
Re: Engine Dying and Jerking

check cps and o2 sensors also try pulling plug off map sensor see if any change in way motors running these are 3 symptoms of what your describing
 
Re: Engine Dying and Jerking

Cleaned the battery cables and everything. Problem is still there. Could it possibly be fuel injectors? i didnt get new ones when i put in a new engine. thanks
 

Re: Engine Dying and Jerking

not just battery grounds.....ALL grounds. On the firewall, on the block, on the frame...ALL grounds. Maybe even take a die grinder to get down to bare steel.
 
Re: Engine Dying and Jerking

umm..could be the CPS like 54cjb3 says. But from my experiance, they either work or not. ECM going bad maybe? Anyone else got any ideas?
 

Re: Engine Dying and Jerking

Well i have no idea if i even put the CPS back on when i installed the new engine (lol). but where is it exactly so i can check
 

umm..could be the CPS like 54cjb3 says. But from my experiance, they either work or not. ECM going bad maybe? Anyone else got any ideas?

Is your transmission bolted tight to your engine, i would check that

My guess is that it's one of these.

If the ECM is going bad it can cause the Jeep to run badly; I just replaced my ECM, and while my Jeep was running good before, it's actually running better and idling perfectly now.

If the transmission is not bolted on tight you can get some mean vibrations in the clutch and flywheel if you have a manual.
 
fuel filter? i have a 2.5 in my yj and that same problem almost drove me crazy trying to figure out what it was and it was my fuel filter. just a thought...
 

I just read "Jerking at 2-2200RPM" and laughed my ass off, other than that, I have nothig constructive to add to this.
 
Okay i have an update that may help describe further. Every time i start my jeep from a cold start and go to drive off, the jeep hesitates when i push the accelerator, and its almost like i can hear each cylinder firing or exhausting one or another. Sometimes while driving i can feel the engine go under strain then go to normal then go under strain then go to normal im not sure how else to explain that i can just feel the differnt vibrations in my feet, this only happens at a constant speed that i can find. Then also im thinking it could be out of timing, when the engine is idling i can stand behind it and listen to the exhaust and it sounds pretty nasty and about every 3 seconds i hear a misfire maybe or something fired to late, and also everytime that happens it looks like carbon comes out and i can see it all over the concrete. Another problem im having is that sometimes the jeep will have alot of power. And other days it will have barley any, almost to where i have to be WOT to keep up with traffic. Sorry that this post is kina un-organized. im very frustrated because ive been driving it like this for 10 thousand miles and it does it 85% of the time im driving... But thanks for taking time to read this and i hope i get some more ideas!
 
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