Problems with gauges dropping to zero and/or spiking and Jeep stalling
I just started my vacation and I'm taking the jeep. Unfortunately it has started acting up severely and I can't seem to figure out what is wrong. If anyone has any ideas, I would greatly appreciate it.
The issue usually happens while driving down the highway, usually 50-60mph, while under light load such as a hill.
The tach suddenly drops to zero, then spikes back up to the proper rpm (This happens so fast it took me a while to notice it). There is a sudden clunk as the slack is taken out of the drivetrain. The speedometer quickly drops about 15mph then spikes back up to proper speed. The oil pressure gauge slowly drops to about 20psi, then slowly climbs back up to about 60psi.
All of this happens within about 1.5 seconds, just to put it into perspective.
I've also found that something similar happens at idle, at random times.
The tach will drop to 0, the engine will stall, and the oil pressure will drop to 0, then slowly pick back up. On rare occaisions, the jeep will die completely when this happens at idle.
Please help, nobody has been able to give me a solution.
Yeah, I sure do... Pretty cool to find you on here. Yeah, it's the same problem. But ive been able to figure more things out and really see what it's doing on this trip. And it's increased dramatically in frequency. So I would like to figure it out before whatever it is dies completely.
There were two times on all my years of driving that my gauges went nuts. 1st was the tach in my 2001 dodge truck, turned out to be a crankshaft position sensor. Second was in my jeep. All the gauges started going haywire like it was possessed when I turned on the ignition key (don't think it would start though), it was a bad battery that time. Good luck.
Ok, Update. I checked the battery, it's good. Scanned codes again. Nothing there. I have an after market alarm and thought maybe it was the starter kill. So I unplugged the alarm completely. Still doing it. Any ideas? I'm starting to think its the computer.
My wife's XJ was doing the same thing a couple of years ago. I was at a loss and took it to the dealer. They said it was a ground wire. It seem like it might have been behind the engine to the firewall. I would check the main ground and any others you can find. I hope this helps.
I would still suspect the battery. I had this happen, although not while running; just when I tried to turn it over (gauges spiking, etc). When you had the battery checked, did they just check voltage, or amperage also? In my case, the voltage was fine, but amperage was too low.
If nothing else, I would suggest trying a similar battery from a friend, etc. and see if you have the same thing happen. If no problems, you know for a fact it is the battery.