Driver Information Center error codes and electrical issues

My Eighty Eight Royale LS is having some trouble being a reliable car. Wonderful to drive when it works, but its undrivable as it is now.

It has a control pannel, (shown in pictures with the error and code for it) very helpful, but when I rev the car (driving or parked) to about 1400rpm then quickly release the pedal, the revs drop down to 200rpm and it stalls. Then it starts dinging and that message shows. There are some other problems with the vehicle, but those are obvious and aren't electrical, such as an inch of oil sitting on top of the engine coolant (most likely from a faulty head gasket?) And a scraping noise while using the extremely worn brakes.

Any help and information you have on problems such as these would be extremely helpful, but I really need help figuring out what is causing the stalling.