Hey there,
I've been around the internet for a while searching for this problem of mine, it has made my XJ the laughing stock of other offroaders...
The other day I was trying to pull a nissan tida out of a bit of sand, I hooked it up to my car , put on the 4wd hi and no matter how much i increase the throttle, the engine speed would not go higher than 2000 rpms. i tried hooking it up from the front so i can use my reverse gear, and the same happens. I then used the 4lo and dragged it out, but just bearly.

Another time , i got stuck in a bit of sand while desert driving, whatever i do, flooring the throttle will not increase the engine speed over 2000.

even once i was drivng up an incline in a parking lot in 2wd, i've floored it and it wouldnt go higher than 2000.
I've been told its a bad tranny, that its not selecting hte right gear, but this happens even in reverse..

Whats wrong with my car?

I've searched everywhere and no one seems to know whats wrong with it, so i came to where i think the Xj pro's are.

Please help.
thanks in advance.
1999 Xj 4.0 liter I6, Automatic 4 speed transmission. Fully stock except for a performance air intake filter and 4inch lift.

 

Is you check engine light on ?

 

do you have more rpms in low 4

 

My first though is the RPM sensor on the transmission. but it would also shift hard into gear while driving down the road if this was the problem

 

does it do this ih 2wd also

 

knock knock any body there

 

yea, it shifts hard drivign down the road, ill get a bump with gear changes,
my check engine light is not on. I changed the fuel sensor almost a year back, i dont know if that is relevant.

If the car is not bogged down or tied to something, the engine runs freely, but if ti comes under load it gets like this.

 

what year and motor and gearing is it does it rev up good in park

 

starting out in 2 gear?

 

yeah I'm thinking RPM sensor

Basically if it's the RPM sensor the transmission does not know when to shift down or up for more or less power

I think the sensor is only forty bucks

 

its a '99 xj , 4.0 liter. Stock gear, stock differential ratios. In park, in neutral , it revs up fine, under load, it goes nuts, or doesnt go at all,
I thought it was starting out on second gear but it also happens in reverse, so i dont know what to make of it

 

I thought it was a saftey mechanism in the XJ to keep it from destroying something, this rpm sensor, does it need reprograming after installation ? Also, can I do it myself or should I take it to a shop?

 

ever check the timing if its adjustable does it shift all the gears

 

If you Let off the gas a little right before it shift does it shift better?

 

if i ease off on the gas when it wants to shift up its usually smoother than when i go full throttle on it