Hi I have a 1995 jeep wrangler that I just purchased. The oil pressure gauge reads 80 pounds all the time I opened the hood and noticed the eletrical plug was off the oil pressure sending unit. I reinstalled connector and now oil pressure reads zero at idle or 3000 rpm. Do you think sending unit is bad or do I have low or no oil pressure? Thank you very much. Toz.

What I would do is put a test light on the wire connector at the sending unit. It should pulsate with a 5v circuit. So it won't be that bright. It also should ground the gauge and cause it to go up (or down in your case) with the key on. We know the needle moves already so that wire could be shorted to ground. Someone knew there was a problem there. That's why it was disconnected.
Try an aftermarket sending unit from AZ. Should be cheap. I don't think you have 0 oil pressure. You'd have some pretty noisy moving parts in that motor.