Hey, I'm having a small problem. Firstly, 4.0 93 AX15 4x4 (brand new clutch/slave/master etc)

If I'm in 3rd gear or higher, when I release the clutch and put it in neutral, the engine will rev down to idle and keep going, often killing the engine. This is bad because i lose my brakes, which I usually need when its in neutral as i slow down. Usually I catch it and restart it by putting it in gear.

What could be causing this?

 

There could be several issues in play. Need some more info.
What you mean with " will rev down to idle and keep going, often killing the engine"?
Does it always shut off while idling? Stalling issues whilst driving?
last Tune-up done?

I'm not sure if manuals have IAC valves, I reckon so, clean that too.

 

if I rev the engine while not moving (aka engine not under load), it will return to idle just fine. If I take it out of gear while moving at speed, the rpms drop lower than idle, and sometimes enough to where the engine just shuts off. It does it maybe 50% of the time. The other 50% it usually drops to 100ish rpms and just picks up to idle.
Have not done tuneup in a while, engine was running perfectly fine until I replaced the transmission. Transmission shifts fine and shows no signs of malfunction.

Also, important, I also removed the muffler. I didn't think it would have much effect because my last cherokee didn't have a muffler and I have seen plenty of str8 piped XJs

 

The tune-up is a good thing to do if due, if only for future reference. Once thing less to worry about.

Has this problem occured right after the transmission replacement? Than work done needs to be reviewed.

Also check TPS.

 

The problem occurred directly after the trans replacement. The exhaust was cut along with the trans replacement. I did the swap, everything apart form that works fine. Shifts fine, clutch is completely disengaging.
It usually won't do it in 1rst or 2nd...

 

Also, more info. I fixed a few vacuum leaks that I saw, no change. When it stalls, it doesn't buck or jerk. Sometimes the only way I find out that it died is when the steering goes stiff along with the brakes.

 

Hey,

I have a similar problem (Posted thread here: https://www.cherokeeforum.com/f2/2-5...sensor-134200/)

I think it might be the crankshaft position sensor.

I found a way to stop the "stalling" from happening though...
When you need to slow down for a traffic light or something, just make sure to depress the clutch as late as possible, so, it remains in gear until you have lowered RPM to about a 1000.
I noticed the problem mainly happens when the revs fall of quickly. It also happens when changing gears up, if I'm not fast enough shifting it into the next gear and letting go of the clutch. In that case, my work-around has been to either be very quick about changing gear, or by keeping my foot on the excelerator pedal, thus keeping up the revs...

One difference compared to your problem though... "bumpstarting" doesn't do it for me, I actually need to depress the clutch, turn the key to off, and basically restart the engine... Not a nice task while going through a junction

 

Yup your situation sounds very similar. It never dies on me while changing gear usually. I can see how a CPS might do it because I did touch that when changing the transmission. \
Your method however doesn't work for me. What I do is let off at higher rpms and feather the throttle till it finds its idle. Someone suggested the IAC valve as the culprit. I have been dealing with much more major problems recently, so I haven't addressed this one. I will try cleaning the IAC valve and see what that does.