Check the wiring to the oil pressure sender, it could be failing, or starting to break.

Fix the aftermarket oil pressure gayge.

Next, QUIT with the fram filters... Get a good filter.

http://www.dsmtuners.com/forums/maintenance-repairs/433196-oil-filter-cut-away-fram-wix.html

The oil light warning is NOT a low oil level warning it is LOW PRESSURE warning. I would double check the wire on it. If it looses connection it makes the dash light pop off. You may have just lost intermitten connection do to the wire clip being old from the 90's

Oh, and do yourself a favor and STOP USING FRAM OIL FILTERS. They are wal-mart garbage from hell. Cut one open and look inside. The end caps are made of cheaper cardboard than a luckycharms cereal box. No joke.

Buy napa, wix, or bosch oil flters. Purple oil is to expensive. You can get valvoline synthetic. Its BETTER and cheaper. This way you can change your oil every 2000-2500 miles like a normal DSM'er does.

It would really bother me.

Consider replacing the oil pressure sender before driving the car again.

When you get underneith the car you will see two differant oil sensors next
The oil filter. The BIGGER round one is the pressure sensor for the factory oil pressure gauge. The smaller round sensor is the low pressure warning light AKA dumby light. This smaller sensor is the one you need to scope out. Double check your wire on this smaller one

I found the attached photo in an older thread. My setup looks pretty much the same, except the pressure sending unit has two terminals on it and goes to a pillar mounted gauge. Aftermarket I assume. One wire off of it goes to ground on the body and one goes back inside the firewall. This gauge is not working. I tried cleaning the terminals and snipped the wires shorter and re-stripped them so I would get a cleaner connection. No luck there. Should there be 12V from one of the wires? What about resistance across the terminals?

There is a wire which goes across the photo. The blue one goes into the left side of some kind of black plastic connector and comes out as a black wire on the right. In the photo it looks like it may go to the pressure sending unit. Is that correct?

OK, mine doesn't do that. The wire comes out of the harness and goes into the black connector. Nothing comes out the other side. Is that because it is not needed due to the newer sender and gauge. The idiot light wire ( I assume since it has a female spade connection) is not connected to anything. I think the spade probably broke off the sender at some point in the past.

So. why is the idiot light going on and off? It seems to flicker in time with most of the bumps, stays on for a awhile, stays off for a while, or just stays on. Could the wire be grounding on something nearby and would that kick the light on? I moved it away from where it was hanging but haven't driven it yet today.

As far as a filter goes, my favorite bang for buck filter is the Purolator PureOne. You can get them for around $6 and IMO they filter better then a Mobil 1 or K&N filter that are like $15.