im new to the Xj world. bought one and wrecked it 3 days later before i could even use 4x4. took my new to me one out tonight ( 98,4dr,5speed,3.5 lift,30") and we did a little trail down teh street.
theres a crick you gotta go through that is a pretty big ravine. i couldmt make it in 2 so i locked it in and when i did i really had to rev it up and almost dump the clutch to get it up teh hill then had to feather the clutch to keep my RPMs up or it would die. any ideas? im kinda mechinally inclided so you can throw tech. terms at me. need to figure this out. kinda lame having a 4x4 that driving in 4x4 up hills is hard

 

Is it really hard to shift into 4hi or 4lo? Any unusual noises? When you are in 2wd does it seem like your jeep wants to cut out just like in 4wd?

 

no in 2 its fine. i get stuck lol. and no it shifts smoothly amd silently.
it does sometimes just die when im coming to a stop light. and the idle is rough sometimes and then picks up to like 1K rpms. i have only had it for two weeks put roughly a 1000 miles on it. runs great besides those two issues.

 

put it in 4Lo not 4Hi when wheelin, oh and clean the sensors on the throttle body, new spark plugs, cap rotor and plug wires. she'll be happy then

 

^ x2. 4 low when you are offroading. 4 hi is still a 1 to 1 ratio. 4low is 2.72 to 1. Use 4 high for like winter driving and such.

 

Sounds like you should've been using 4 Low. Also sounds like your TPS is on the way out

 

I agree with these guys. You have something going bad and its intermittent which to me is the worst cuz that thing that is going bad will work when you test it but as soon as you start driving it will fail. One thing you can check that isnt posted is your fuel pump. I had one that was intermittent and it would give this whining noise every now and then. When the whining occurred I had a rough idle and putting a load on the engine made it difficult to keep the engine up. Then, After a few days it make no noise....it died. lol
Let us know what you find!