alright so my brothers '80 bronco with an '88 351 loses "oil pressure" on the highway and highway only. streets are fine. I was wondering if the gauges go out like this under a constant pressure.

new sensor, 10W-40 castrol gtx with lucas oil stabilizer if it helps.

 

Is it RPM related? If he holds the gas in neutral at highway rpm will the pressure still drop? I had a new sender, that would read normal and as soon as I gave it gas it would drop. I ended up getting another new sender to fix it.

 

Also, small block fords are famous for keeping oil in the top end at higher RPM's, especially if the oil galleys are dirty.