npmagnifico07

ok so i have a 98 xj its been really good to me till now. the jeep starts up fine and ideas fine, even revs up fine but soon as i put it into drive it starts missing and sputering and barley even moves at all. i put it in 4lo and put it into drive and it stalls right out. but the weird part is i can start it and put it into reverse and it wont miss a beat and will run and drive fine with no miss or sputering or stalling. i replaced the map sensor and tryed a different ecm. also checked under the cap and rotor all looked fine....need help please.

npmagnifico07

any ideas are a help

Muaddib420

Is it throwing any check engine codes? First cheap easy thing you could try is refreshing all your grounds and make sure battery cables are tight. Second, new plugs.

npmagnifico07

it did have a cel on at one time but it went off. ill go over the grounds and plugs tomarrow. its just so weird that it runs great when in reverse but soon as i put it into drive it starts missing and barley run.

Cherockee

A loose wire I would think- and probably bad motor mounts and tranny mount. In a forward gear the torque will twist the motor one way and then in reverse the motor will twist the opposite way.

Roler

It appears the issue is misfiring/stalling/shutting off under load only, since starting and idle are fine. Unlikely to be related to bad engine mounts per se.
This will need a somewhat systematic approach, because several things can be in play.
THe CPS (Crankshaft Position Sensor) can cause the symptoms, is known to fail at some point during its life in the 4.0, and if not replaced, might be a very good time. If replacing, get a quality one. (when mine went bad, it started and idled fine, but randomly made the engine stall whilst driving, replacement fixed all this)
The TPS (Throttle Position Sensor) could be off/bad, giving the incorrect information to the PCM, and as a result disbalance in air/fuel mix to the extend of stalling.
Battery good? Yes, a battery can be ok enough to start the engine, but might be not good enough once load is being put on it.
Other issues might be in play, but these are ta few things that jump to mind for now.
And a tune up and refreshing grounds is a very good basic if not done yet, for future reference.
Others will likely have more/other input. See how you go and let us know.

npmagnifico07

im going to go over all these things tonight at my garage. and i also posted this problem on jeepforum.com and i guy responded by saying '' Bolts are loose that connect bell housing to engine block. (someone else had this problem not long ago)'' so im going to look into this as well. ill post tonight to let everyone know where it stands