OK, I have a couple of questions here about the oil pressure gauge. I installed a replacement engine in my 87 4runner out of a 85 4runner. When I started it, everything worked fine except the oil pressure gauge...it kind of jumped around a little bit and then just slowly went down to zero. I installed an aux. oil pressure gauge and verified the engine is making oil pressure so I removed the 85 pressure sender and installed the original 87 sender, but the gauge still doesnt work. after some research, I see that there is a difference between the sender for the idiot light and the sender for the pressure gauge. On top of that I read that if the wrong sender is used it can fry the cluster gauge....this is where I think I am at. My questions are: how to tell the difference between the sending units, and what can be done about the gauge? Can it be repaired, individually replaced, or do I have to get a complete replacement cluster? (I never saw the donor vehicle so I cant verify if it had a light or gauge)