I recently purchased a 1996 Grand Cherokee LE with the 4.0 and roughly 195K miles. Needed a CAT, so I installed and passed emissions. Started driving as daily driver in mid August. About two weeks in, it died waiting at an intersection, but restarted right away. There are some wonky issues with the electrical system on the interior, but I didn't think they were related. Recently it has been dying more often, three times on the way to work yesterday. It's getting harder to re-start. Could this be a voltage regulator issue? Perhaps ignition related, or am I experiencing a fuel pump going out? Dirty injectors?

Also, but possibly related. The heating/cooling system is buggy. When I turn on ac or heat, it will cycle through the various settings: floor, defrost, panel, etc. Then it will sometimes just turn off. Other times it will come on when the switch is turn off. Sometimes AC blows hot, etc.

I get that the electronics are old, but is there something I should be looking for such as a worn connector etc.?

Any help would be greatly appreciated

 

Welcome to CF!

Random stalling, just shutting off, then restarting like there's no problem, is a common symptom of a failing Crank sensor. It's a magnetic switch on the bellhousing and looses it's magnetism over time, especially if it's not a OE sensor.

The heater is probably the automatic climate control, right? It's a complicated electronic unit and hard to service. There are actually temperature sensors at various places in the cabin that control it as well. I'd look into replacing it or swapping to a manual unit.

 

So, I changed the Temp control module (onboard computer said it was bad), changed the Crank sensor and it kept stalling. Put it on a computer and it read P0351 Ignition Coil Pack, so I changed the ignition coil. ran great for about two days and now has stalled at least once per day since. Twice today. Haven't had a chance to put it back on the computer yet.

Ideas?

 

The 4.0's can do weird things with dirty grounds. There are quite a few of them in the engine bay. It's a free and wuick thing to do and rule out. Google the locations, you should fine a picture with all the info.

If it still does it, maybe tried removing and cleaning the throttle body and IAC valve.

 

ok,

similar issue to what i had in my 1996 grand cherokee.

its about a 30-40 dollar part or cheaper depending on where you get it.

but look at possibly replacing the ignition coil pickup others call it the cam sensor but you'll never find the part like that.

it sits under the distributor cap and rotor. i replaced those and the wires at the same time.

how things was replaced

i had spark and fuel

replaced crankshaft position sensor, ran great for one day then no longer would start

replaced ignition coil, again ran great for a day or two and then would no longer start

replaced the distributor cap, rotor, wires and the ignition coil pickup, been running just fine for 2 months now.

 

Here's what I've done so far:

CPS - replaced
Temp sensor - replaced
Ignition coil - replaced
fuel filter - replace (figured, what the heck)

Plugs, wires, cap and rotor were all replaced last year.

Had my mechanic neighbor with his hoopty computer take a look today. Of course, it ran fine the entire time he was here. His computer showed all systems running perfectly, while it was running. So no clues there. There is definitely a bug in the system. That being said, I haven't tracked down all the grounding points yet.

I took it for a drive after he left and it died on my street, but it did something weird. It shut off and coasted, but before I could do anything, it restarted on it's own while I was still rolling.

 

RGS posted what I suggest also. Replace the cam sensor. Mopar only on that baby too or you will have nothing nothing but problems. Even go to the junkyard and pay $5 for one just to see. Thats what I did 3 years ago and it has been fine. However both brand new aftermarket sensors crapped out within weeks.

 

ECM was bad. Pulled it out and checked the contacts, 2-3 were loose. New Computer and it's running fine, no more stalling.

However, after a week of driving I suddenly have a P0420 code. But the O2 sensor and Cat are both new! What the heck else would cause that code?