ongoing non-consistent problem

I have been trying to figure this issue out for about a week and a half and thought i had, but its back.

I have a 91 jeep cherokee 4.0l and this summer i replaced the engine, everything has been running great but as the snows been falling, i've been chasing a vacuum leak somewhere because my 4x4 won't engage.

There was a storm and i was trying to get around in it and got stuck, eventually i got out but since then i've been having this issue where i'll just be idling or driving along and all of a sudden the engine starts cutting out. almost like your just cutting power to the engine and nothing else but only for a second at a time, the rest of the power never gets interuppted. Eventually or right away it will kill the engine, then the engine starts up and runs again or it'll happen again. Its very sporadic and frustrating me to no end.

i replaced the TPS, i replaced the CPS, i thought maybe the fuel pump, but normally fuel pumps just go out in my experience. This seems to be some kind of moisture problem, but i'm not positive on that either. Anything anyone could give me on this would be great and helpful.

One more thing, my vacuum leak. I have checked all the lines and they are tight with the exception of the one that goes into the cab. Where does that one go? I can hear it when its leaking but it only happens when i'm driving.

The cutting out problem is probably a bad ground... I would check something that I found on my 88... If you have air, the air conditioner plumbing runs directly over the positive terminal, and on mine, the positive terminal was arcing to the metal fitting on the air conditioning line. Caused a similar "engine kill" symptom. But the BOTTOM LINE is checking those grounds!

i tested the vacuum canister and blew into the line for a bit, then it just came right back out, seems fine. There is one line that goes in to the cab through the firewall behind the heater, does anyone know where that goes? cause i can hear it whining,

I'm going to run a second thick ground wire to the frame and to the engine for the cutout issue, but i have a hard time duplicating it.


Any other suggestions from anyone?

Superflie said:

i tested the vacuum canister and blew into the line for a bit, then it just came right back out, seems fine. There is one line that goes in to the cab through the firewall behind the heater, does anyone know where that goes? cause i can hear it whining,

I'm going to run a second thick ground wire to the frame and to the engine for the cutout issue, but i have a hard time duplicating it.


Any other suggestions from anyone?

Click to expand...

The heater controls are vacuum operated. Whining there could be from a leaking control valve or lines to it, or a leaking or disconnected line to one of the flap actuators. See if you can make the whine change or go away by altering some heater settings.