Low idle and stall

I have an 1987 Xj with a 4.0L and a AX-15 5 speed. The problem is that it will run fine but when you push in the clutch the RPMs drop to zero and it sputters and then dies. It does this in gear and neutral, as soon as that clucth goes in it does it and now it is starting to do it all the time it just doesnt want to idel. I put a new Crankshaft position sensor and Idle air control valve on it. It still does it, anyone have any suggestions?

Not sure about this, but:
How is your battery? On the late models(OBDII) if you have a bad battery(even with enough juice to crank the jeep reliably) you will get a low idle with no other symptoms. I don't know if the older ones will do the same thing.

The only thing I can think of that would do that is a siezed up throw-out bearing. Or so much crankshaft endplay that the CKS (crankshaft position sensor) can't read the flywheel notches.

so.....if its out of gear clutch out it runs? if you give it gas while clutching does it run, or sputter and die? need more symptoms/details to a fine degree.

89RockHeep said:

so.....if its out of gear clutch out it runs? if you give it gas while clutching does it run, or sputter and die? need more symptoms/details to a fine degree.

Click to expand...

Yea if its in neautral and the clutch is out it runs. As soon as you push the clutch in it dies unless you gas it to about 2500 then it wont do it.

Could be some form of drag in the clutch assembly, as stated earlier. Might be something wrong with the CPS in relation to the flywheel under pressure.