When I idle or drive at low rpms, my oil pressure goes to 0 but when im driving it usually runs at 40...

 

Very likely you have a bad sending unit.A mechanical oil pressure gauge Tee'd in to the oil port is the only way to know for sure since you might need the switch to run the LP.
AC Delco only for electrical replacements,BWD are very bad switches.

What year engine?

 

95 in a 94 Body

 

Should be no issue wiring wise,get a delco sending unit and google "OPS relay mod" while you are at it-it is worth the effort.

Check LP operation as well.

 

Alright thanks

 

where is the oil pressure switch on a 1995 6.5

 

Should be just in front of the fuel filter manager in the engine valley.

If you have a later model block it could be tucked under the intake closer to the middle/rear of the valley.