Fivefifty%

My jeep (1995 Cherokee Sport 4.0) has a missing or bucking problem, it does not do it all the time and it feels like a fuel starving problem or loss of spark. During acceleration and steady throttle it starts to buck and feels as if it could be running on less than 6 cylinders. If i push the gas pedal to the floor it will accelerate/hesitate but sometimes pull through it. Parked or sitting at idle it will miss badly on and off. It did this about 3 or so months ago and I put a CPS sensor in and it fixed the problem or so I thought. Only things that are not new or less than 6 months old that i think could be related to the problem are the distributor, coil and fuel pump. It has new plugs, wires, rotor, cap, crank position sensor, injectors, fuel pressure regulator and fuel filter. Just looking for some guidance or advice before I throw more parts at it.

RTorrez1

I would start by checking the fuel pressure at the fuel rail with a mechanical pressure gauge. For your 95 it should have 39psi. That's where I would start. But that's me, then I would work from there.

smoker9000

I've had this very same problem, mine would some times back fire through the tb if you held the pedal to the floor. I changed both 02 sensors and it hasn't done it since. A friend of mine had the same problem to the T, ended up being the crank sensor ( a real ***** to change with the engine still in the vehicle) it's located on the top drivers side of the bell housing. good luck

landude

My first question would be where did you purchase the CPS. If it wasn't from the dealer it may be the issue. I had gotten one from the zone and it may have lasted 3 months..

Turbo X_J

^
This doesn't make diagnosis easy. Describe the issue you are having in 1 complete sentence.

Fivefifty%

The CPS did come from the zone. Just 3 months tho? It does seem like it would be the cps again tho since it is the same symptoms.

Fivefifty%

I don't have any backfiring. Yeah the CPS is for sure a pain to change. It's looking like my autozone cps is failing. So looks like I'm gonna have to buy mopar. Thanks!

landude

I would return that to the Zone for a refund, pick one up at the dealer for a few dollars more..

Fivefifty%

$74.95 at the dealer ordered it today and will pick it up tomorrow afternoon! Can't wait to get rid of this bucking problem!

RTorrez1

I hate to say it. But I doubt that the CPS is your problem. Hopefully it is but I doubt it.

Unknown XJ

My '89 that I used to have bucked.....

It turned out the problem was the wire was pulled out of the boot slightly at cylinder #6 and it was arcing over to my transmission dipstick. Pushed it back into the boot and reclipped on the spark plug and was good to go.

I chased it for a week and I just happened to be under the hood at night and saw that pretty blue arc.

Unknown XJ

My '89 that I used to have bucked.....

It turned out the problem was the wire was pulled out of the boot slightly at cylinder #6 and it was arcing over to my transmission dipstick. Pushed it back into the boot and reclipped on the spark plug and was good to go.

I chased it for a week and I just happened to be under the hood at night and saw that pretty blue arc.


Sometimes with these XJ's, its something tiny and stupid that'll make you chase your tail.