I have a 2000 f150 with a 5.4. At start up the oil pressure will drop and will stay like that for awhile then will come up, sometimes it will come up then drop again. it will come up when i give it gas. seems once it is warmed up it is ok. at a light it idles at around 6. seems a bit low? someone told me it is the sending unit but with it going up when i give it gas would tell me it is the pump? any ideas?

 

Idle is fine, what oil, and filter are you using.

 

I had the same issue on my 2000 5.4.

It was oil pressure sensor. The part wasnt too expensive. Getting it out wasn't bad... Getting the new one started however was a pain.

 

Yea, they can get covered w/oil on the outside. Leads to intermittent problems. Your problem sounds more like what troykshafer posts above ^^

Pressure from the factory gauge should jump right up and stay there. Like this, -


Oil pressure @ start.

My old 2001 5.4L -

https://picasaweb.google.com/jbrew39...84705673453298

My older 1998 5.4L -

https://picasaweb.google.com/jbrew39...90121627213570

 

Well, it was the oil pressure sensor! $10 for the part and a few minutes to swap it out! Thanks guys for your replies!