When I accelerate the factory oil pressure gauge drops all the way off and stays there until I let off the accelerator then it come back up, is my sending unit going bad or could it be something much worse? pickup tube fell off or something?

 

Get a 0-100 pound mechanical gauge and install it in place of the sending unit. Run the engine in nuetral while watching the gauge. If the pressure drops, you may need a pump.

 

Mine does the same thing. I replaced the sender a few months back. It seemed to work fine for a while, but is back to the same thing again. My low pres light does not come on when the gauge reading falls to zero.

I'm assuming a bad ground or connection somewhere rather than an engine problem. I just haven't had time to fool with it. I think I've read about that here sometime back.

 

Mine had the same weird quirk. Mine first happened when I bought it - about 500 miles away from home, which scared the crap out of me! I thought I was 500 miles away from home with a new truck and no oil pressure. At about 60-65 MPH the gauge would drop when on the throttle but go up when I let off. I put in a new sender and its been fine since. I'd much rather have a mechanical oil pressure gauge, though.

 

I had the same trouble on my 91. I changed the sending unit. It has worked fine ever since. Mark

 

Now THAT really would freak me out too!! I've never had ANY car or truck ever do that(knock on wood...). All my oil pressure gauges have always gone the other way when accelerating(up). Hope you guys get yours fixed, and it's good to know in advance this may happen...this thread may in itself prevent me from keeling over from anxiety if it does!! Thanks for your inputs, good luck to you all!!