Sometimes my oil pressure gauge goes all spaz, the needle starts jumping all over the place rapidly, when I rev the engine it goes back to normal pressure but then starts again, anyone seen this before, thanks

Sending unit located on engine needs to be replaced most likely.

I agree, that's the most common fault with the system.

Replace it now, mine was doing that then one day 2hours into a 7 hour trip home it blew up on me and being that it was Sunday night i couldn't get parts or even see what was going on. not fun at all.

Did you see the thread about the sending units being mis-wired? Looks like its a good idea to do The Fiero Store ones.