I just bought an 85 Z28 to play around with... the guy told me it has an 87 5.7L TPI. I've been looking around the engine compartment checking out what I can do to clean it up a little bit and I came across this thing that I don't know what it is. It right next to the distributor on the back of the engine.. whatever it is the wire going into does look like its connected very well. Any help you could give me to let me know what it is would help. Its the thing with the yellowish cap.

 

Oil pressure sensor

 

it's a dummy light sender, for oil pressure. it's threaded into the block with the oil pressure cut off switch. i took mine off and plugged it

 

Are you sure? On mine that's the sender to the 60 psi gauge.

If you fool with it, be careful, they're in two pieces and if you spin the top half loose it'll leak. They're a pita to get to as well.