1996 Jeep Country Automatic 4x4 (230k miles)

So within the past two to three weeks I've been having all sorts of random symptoms from my otherwise healthy Jeep. It all started (in my mind) when the remnants of hurricane harvey rolled through Tennessee and we got a lot of rain for several days.

The first thing I noticed was that when I cranked the engine it would start and die. If I gave it some gas and held it for 15 seconds, it would get going and stay running and would start fine as long as the engine was hot. Then for a couple days it would be fine and then I would have the starting problem again. As recently as yesterday I still experienced this.

The second thing is that when cruising at around 30 mph (my average speed on my commute to work), my speedo and tach would suddenly drop to 0, especially when I let off the gas. The fuel guage also would rise all the way to full. I was able to regularly replicate this problem as long as it was raining. After the rain stopped, it stopped happening, until yesterday it happened out of the blue one time.

The third issue is that my oil pressure spiked to 80 a couple days ago, and hung out around 70-80 on my way to work. Afterwards, it seemed to drop down to around 50-60, although it can rise and fall with acceleration from 20-75.

My #1 suspect is what I believe to be a loose and oily ground. I'm hoping that this is going to be related to and solve the starting and gauge problems. The following picture, which I thought would turn out better, is of what I believe to be a ground behind the oil dipstick. It is covered in oil from a valve cover leak that I plan to fix soon, and also appears to be backed out several turns:





My next suspect, at least regarding the oil pressure, is the oil pressure switch (OPSU). It was replaced 60k miles ago, so I guess it's possible that it has failed again. I've read several threads that seem to confirm that this is most likely the problem due to my symptoms, so fingers crossed.

Anyways, I just wanted to run this by y'all to see if there was anything else I should be looking for as I plan to get under the Jeep later today and work on all this as well as changing the oil.

Thanks!

 

Clean every ground you can find in the engine bay first.

 

Just a quick followup if anyone comes across this searching for answers to a similar problem.

I discovered what I believed to be the faulty ground was the one behind the oil dipstick. This was not the "ground" in the picture, which actually was just a bolt holding the transmission dipstick bracket. The actual ground was on the block. It was quite loose and had three wires grounding to it. I removed and cleaned all contacts and my gauges problem has not happened since.

The starting issue was simply a dead battery. Replaced and everything is stronger than ever.

And as for the oil pressure. When the Jeep gets up to operating temperature, it holds mainly at 40, dropping a little when coming to a stop during in town driving and I believe everything is good with it. I think that I got thrown off when the oil pressure gauge acted up, and I started watching it more intently than I ever had before, which caused me to think that it was acting weird, when in fact everything was fine.

 

Excellent job. Thanks for reporting back.