I need help with same issues..... Factory guages-I show good presure at idle, When I give it gas, the presure drops and ligle comes on. Puttering around in town needle doesnt move much but when I get on the freeway it dives to 0 and the dummie light comes on. I need help 95' 1500 240,000 and still runs great just starting to give me fits

 

Could be a bad oil pressure switch.

 

And where is that. I am a part changer not a mechanic. I have the Haynes book and cant find anything on it. I was told to put in a guage but have no idea where or how???? Thanks

 

sending unit is on top at back of motor. To the left of distributor

 

V-8 y?

 

I am. And it should never register zero at any RPM.