Odd problem: When I first start my 86 944 in the morning, the oil pressure gauge reads 5 bar. This is normal. The low oil pressure light comes on though, and the idiot light comes on as well. After the car warms up, the oil pressure gauge reads 3 bar [this is also normal] but the oil gauge light will begin flickering on and off several times each second, causing the idiot light to do the same. I've never had low/high oil pressure, nor do I suspect that's the case now. Is there a problem with a sensor/sending unit/or the gauge itself? Perhaps a mechanical problem I do not know about? The engine is running strong, I change oil every 2500-3000, and 115k on car. What's the deal? -Trevor

 

sounds like the oil light wire is shorting out, check the connection and wiring around where it connects to the sender.
Martin http://members.rennlist.com/martintaylor/

 

I had a similar problem. As Martin recommends, check for a short.

In my case, there was a piece of metal tubing that was rubbing against one of the leads of the oil sender, causing a short. I moved the tubing a bit and I put a liberal amount of electrical tape around the tube (in case it happens again) and the problem went away.

 

Where is the oil pressure sending unit located? Thanks. -Trevor

 

Again, I bet it's the oil pressure sending unit. Just like the other fellas post. These symptoms sound similar to mine, and indeed it was that for me.

The unit is located almost directly underneath the oil filter (I assume you know where that is). Take that a few inches down and towards the center of the car. You can't miss it. It's a little deal with a few (probably 2 or 3) wires coming out of it depending on your year I think. (You'll probably have to go up at it from underneath the car). When I changed mine I had to remove the oil filter. And don't forget when you put it all back together again add the amount of oil that you lost from the dripping.

-M