The oil pressure "gauge" in the dash of my 1987 Camaro isn't working. It sits on the bottom. Occasionally it bounces around and sometimes reads right. I just put a 383 stroker in and know it has oil pressure because I have a autometer mechanical gauge hooked up under the hood.

I know the dash gauge isn't all that accurate, and I know there is good oil pressure, but it is still a bit worrying driving around and the gauge reads zero.

What parts should I look into to see if I can fix this. Loose connection in the dash?

I installed a brand new sender when I put the motor in. It did the same thing with the 305 up until I pulled the motor.

 

A bad wire connection on top
or maybe ground wire

 

I took the gauge cluster out, cleaned and tightened the contacts and put it back together. The gauge works now but is very jerky, it doesn't go up and down smooth but jumps up with rpm, sticks, let off gas and it jumps down, sticks, ect. Probably as good as it will get.