this might have been covered before but i have a concern.

today while i was driving home from work, someone flashed their headlights at me so i started looking at all the guages and checked the mirrors for fluid dripping on the road.

didn't find anything out of the ordinary, but what did catch my eye was whenever i let off the gas my oil pressure drops to 0psi and when i accelerate it goes back up to normal. btw its an aftermarket gauge.

should i be concerned about this?

i know that the lines are good and all the connections are tight.

 

I get that when my engine is a normal op temp on the stock guage after about 30min of normal driving.I've been told it's probably the oil pressure sending unit.Is yours the stock sender?

However,if yours has an oil line right to the guage and the guage is good,you could have a low idle speed.What rpm do you idle at?
How's your oil filter?

Worst case scenario is a bad oil pump.(Let's hope it's not that bad)

 

its not stock, its an aftermarket mechanical one.

it usually idles at 600-700rpm but the last few days it has been idling at 1000rpms and stumbles as it drops down rises back up and then slowly drops back down to 650rpms

and i'm sure the oil pump isn't bad yet because i'm still able to drive it.
if the oil pump had gone out i'm pretty sure my truck wouldn't have made it the rest of the 20mile trip from work.

 

My '99 V6 stays about 40 P.S.I. at idle when warm with stock gauge with 166K on it. As far as your idle, I'd look into your IAC.

 

Ya sounds like a bad oil switch.