95 YJ 4.0 surging upon acceleration

laneiac

New member
When I take off from a stop or a rolling start in 1st gear, the jeep seems to not make any power between 1500-2300 and then all of a sudden the good ole 4.0l torque seems to "kick back in" and pull me up to redline. Power delivery used to be smooth from the get go and just pull without any problems, but this "stalling" is really getting to me. I was thinking bad plugs and wires perhaps, maybe even rotor and cap though they were changed not to long ago.. Any suggestions would be greatly appreciated. Thanks, Lane
 

i get that ALL the time... ever since i've owned it... i haven't been able to find what makes that flat spot
 
One of two things that I can think of-

Definitly a fowled plug or something in the ignition (cap, rotor, wire, etc..) make sure your timing is dead on or the ditributer will miss fire under load

second it could be a catalitic converter, but you say it goes away in the higher RPM range so I would tend more to the ignition!
 

Ok Lane and all you smart jeep people, let's figure this problem out :D

My 95 4.0 JUST started doing the exact same thing yesterday. Here is the scenario so maybe we can solve this. I went off roading, same as I have done before, the only thing really different was going out to the site i was going about 60 on a very bumpy road. Like riding over 100 speedbumps. It litterally shook the hell out of the jeep. After that long and bumpy road is when this problem started happening. On mine it is intermmittent, with the problem occuring around 70% of the time. I seems to only happen in first, second, and rarely third.

So any ideas from you Jeep Gurus?
 
I would say start by checking the timing. It would be unusual if it the distributor lockdown came loose, but you never know.
Try advancing the timing a few degrees over stock and see what happens. You can alway put it back.
 
Check the CPS (Crank Position Sensor) on the driver's side of the bellhousing, just behind the intake manifold, make sure it's tight. Make sure all your vacuum connections are tight and that you have no vacuum leaks.
 

Definitly a fowled plug or something in the ignition (cap, rotor, wire, etc..) make sure your timing is dead on or the ditributer will miss fire under load

second it could be a catalitic converter, but you say it goes away in the higher RPM range so I would tend more to the ignition!


brand new ignition in mine... no cat.... i still get it... fiddled with the cps... i think my o2 sensor is bad
 
lift kit

I had this kind of problem, i replace everything related to ignition...since this problem occured randomly, it was real hard to find out the problem. After replacing the rotor, cap, spark plug, TFI upgrade, it ended to be my Ignition module ( located under the prestone tank in my '88 YJ) a wire was probably half-cut so it turns on/off while i was driving. By the way, i relocated this module near the front driver's side wing.

Bert
 
Thanks for all the suggestions guys, I am going to be looking into it this weekend after I finish the clutch on the lil lady's YJ.
 
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