I let my 96 Cherokee Sport, 4WD auto, sit for the last year, starting and running it only occasionally. Bought it new, 233K miles. Been an excellent vehicle. I would go buy a new one just like it today if they still made 'em.
A month ago I put it back on the road. Pretty soon I had a no start. Changed the crank position sensor (third one), started and ran fine.
Next time I started it, it ran like crap, idled really rough, and stalled repeatedly trying to pull the M715 into the shop. I did the easy stuff, like fresh gas, gumout, etc. Checked/cleaned all of the grounds that I could find in the engine compartment. Switched/checked the relays in the box. No change.
Started and ran fine the next day.
Slowly I started to see a pattern. If I honk the horn, the Jeep will stall. I unplugged both horns, and it will still stall, so it isn't a horn. (No cruise in the column) Sometimes, but not every time, if I turn on the headlights, or the wipers, it will stumble just a little and then settle out.
Been keeping it pretty close to home, but it has run perfectly on a couple of 30 mile trips, at dark, with the lights on.
Yesterday, and I swear that this happened, my wife started the jeep with the door open, and it wouldn't stay running. I could see the exhaust and it was belching black. I told her to keep it running and started to brush snow off of it, so she shut the driver's door. The idle settled right out, and it ran fine. Open the door, it ran rough. She said that the tach needle jumped all over the place with the door open, but I didn't see that. Door closed, tach was fine.
To me it has to be a ground issue, probably at the PCM ground,or possibly under the dash. I myself have never seen the gauges fluctuate, and they all seem to be accurate. When it is running, it runs great. The problem is very intermittant. (I did start it again later and mess with the door jamb light switch--no change in idle, ran fine) No power locks or windows in the doors.
Can someone tell me where the PCM grounds, and where the ground locations are under the dash?
I searched, but I wasn't able to find this problem in the forum. If anyone has had this problem, I'd love to hear how it was fixed.
The engine light is on, (has been for a long timelong before I quit driving it last year. It shows 02 sensor), but it has never affected the driveability.
I would really appreciate any thoughts concerning this problem. I have to admit, running rough with the door open is a new one on me!

Thanks,
Greg
'43 GPW, two '45 MBs, '51M38, '52 Hot Rod M38 pickup, '96 Cherokee

 

Ground for the pcm is on the driverside fender just behind the airbox, under the wiring harness. You'll see two smallish, short wires. Also check the engine ground and battery ground. Then if you want you can add a couple more grounds. Welcome to 96 xjs lol. I have two of them.