Oil Pressure

My Oil Pressure Is Normal Until I Drive For Maybe A Mile. After That It Drops Down To Nothing. What Possible Things Will Cause That? IT'S AN 86' F-150. HELP!!!

haha mine does the same thing... i made a temp fix to the prob...but its ur oil pump. dont let anyone tell u its the oil sending unit, i replaced mine, didnt help. its ur pump...but if u dont have the cash at the time like me, get some 15W40 oil and put init, it will fix it till u get a new pump, i put it in mine 90 miles ago and its still fine....

I've Heard It Was My Bearings. Some One Else Said It Was My Cam. I'm A Street Wise Mechanic And To Me If Your Pressure Gets Low After Your Engine Gets Hot, Then It's The Pump. If I'm Wrong, Please Correct Me Before I Change A Part That Is Good.

I've Heard It Was My Bearings. Some One Else Said It Was My Cam. I'm A Street Wise Mechanic And To Me If Your Pressure Gets Low After Your Engine Gets Hot, Then It's The Pump. If I'm Wrong, Please Correct Me Before I Change A Part That Is Good.
maybe you should actually check your pressure with a gauge instead of relying on the in dash gauge.it can be the pump, or you can have worn bearings which have excessive clearance.how many miles on this engine?
id opt for 20w50 oil instead.

maybe you should actually check your pressure with a gauge instead of relying on the in dash gauge.it can be the pump, or you can have worn bearings which have excessive clearance.how many miles on this engine?
id opt for 20w50 oil instead.
ALOT!!! Title said excessive! My question is that if it was the bearings, would'nt the pressure be low from the start?