jowad

Hi, I have a 1995 Jeep Grand Cherokee Laredo 4.0L V6 with 194,000 miles. This issue I'm having is accelerating from a stop, roll or already moving but this is an on again/off again issue. What happens exactly is unless i put the exact right amount of pressure on the gas pedal i get no power. The rpms go up and down in a range of 500 or so. Happens mostly between 2,000 to 2,500 rpms but also at higher rpms.The only solution so far is to take my foot of the pedal and start again. Also the car will buck forward and backfire sometimes.

solutions i have tried:
oil filter replaced
transmission speed sensor replaced
fluid added to t-case
fluid added to transmission
up stream O2 sensor replaced (no downstream O2 sensor b/c no cat)
used seafoam (in gas and vaccum lines through brake booster)
changed oil (every 3,000 miles)

other work also done:
new wires, plugs and distributor cap
new front tires
rear shocks
new air filter
new pvc hose

any help is greatly appreciated. thanks!

- Joe

basegrinder

Is it bucking forward, or does it seem like it's just the transmission slipping into gear?

jowad

It is bucking forward while the toms go up and down.

jowad

Sorry "rpms" go up and down.

jnicewan

Is it more pronounced at higher RPM or loads, or is it more pronounced on specific throttle positions? It sounds like either a low fuel pressure concern or a TP sensor concern. TP sensor will usually turn the ck eng light on, at least after a few miles of the concern being in place, but not always. Low fuel pressure usually doesnt trip the ck eng light unless its been running lean for awhile and you would probably see it as a oxygen sensor code.

If possible you might try to scan for codes and test fuel pressure. It would be best to have a fuel pressure guage you can watch while duplicating the concern. If you dont think its fuel pressure you might look into the TP sensor or as a guess replace it. Before any of these steps you might try replacing the fuel filter first though.

jowad

Right now the check engine light hasn't come at all. I replaced the fuel filter roughly 3 or four months ago. I'm going to try the TP sensor first. I got a new just need time to put it in. i'll keep you updated. Thanks.

jowad

I replaced the TP sensor and hope that was the issue. Once I get a chance to drive and see if it acts up again I'll know for sure. If it does Ill check the fuel pressure next. Advice on how to check fuel pressure?

Ex Alfisti

My XJ does that when the fuel level is low. Someone said it is the fuel pump on its way out.

jowad

So far the new Throttle Position Sensor seems to have done the trick but I also think there is an issue with my fuel pump assembly my gas gauge doesn't work. (I already put a new dash cluster in and it still doesn't work.)