I don't know where to go from here.

I just overhauled the engine in my Cherokee (4.0L, I6), and the thing keeps hesitating on and off. Sometimes it stalls out while it's idling, sometimes it stalls out at cruising speed, and won't start back up after sitting for a long while. I've replaced the CPS, idle air motor, and oxygen sensor (emiss. maint. light was coming on). Still not solving the problem.

I have noticed that after it stalls, the pintle in the idle air motor is fully extended. So I screw it back to its specified length, put it back in, and boom, problem solved......temporarily, because the same thing keeps happening.

Any ideas out there???

check and see if you hit,movedor cracked the cps. its located on the bell housing usualy on the driver side. hard as hell to get at but that could be the problem. hope this helps

I have noticed that after it stalls, the pintle in the idle air motor is fully extended. So I screw it back to its specified length, put it back in, and boom, problem solved......temporarily, because the same thing keeps happening.

Any ideas out there???

take the idle-air motor off and clean it, and the throttle body where it extends in.

you say it seems to unscrew to a extended possition, then when you screw it back in it works ok until it sticks out. I'd think it fairly good odds, that it is hanging up in the throttle-body and gradually unscrewing itself as it works it's way back and forth. a little wd-40 and a soft brush seems well worth a try.

I went ahead and got a new Idle stepper motor and cleaned out its seating in the throttle body. It took care of most of the problem, but it still wanted to cut off at highway speeds.

So I replaced the stator (or pick-up coil) by pulling a distributor from a 4.0 L Comanche at a junkyard. It seems to have cleared the problem up.....but I'll have to drive it around to see.

Thanks for the help thus far!