Drove 30 minutes home from a doctor's appt in my 1999 F250 witht the 5.4L and pulled into the driveway to let my dad get the mail, looked down at the dash and the oil pressure light comes on and the gauge dropped, turned all the accessories off and could hear the rollers ticking and rattling from no oil, pulled up to the house shut it off, let it cool for a couple minutes, turned it back on and the same thing happened, shut it off and changed the oil, it rattled for a minute and then quit, and oil pressure was back, light went off, later on it flickered but then returned to normal

any ideas to what may have caused this? I can't figure it out

 

you sure you actualy had no oil presure ? might be a sign the pressure sending unit is failing or getting ready to fail...

i had a 2000 F150 with a 5.4 that had that exact scenario happen. turned out to be a cheap repair getting the sending unit replaced.

i did have horrible visions of a bad oil pump.. luckily it wasnt...

 

thanks i'll check that
the oil pressure was really low
i don't understand how changing the oil would have made it go away though

 

Sorry, but that has nothing to do with the sending unit. It only reports oil pressure, it doesn't make it or control it.

You didn't say how many miles were on your engine, but unless you correct the cause of the oil pressure dropping you'll be replacing it very soon.

Sounds like the entire engine needs to be torn down and rebuilt.

 

its got 143,000 on it, it shouldn't be needing a rebuild anytime soon
so would you think this is a oil pump? anybody know how to change one?

 

What was the oil level before you changed it? Did you run it too low on oil?

 

If the motor was rapping, thats a pretty sure way of telling you either you had little oil or little to no pressure. Did you note how much oil you removed from the engine?
Could be clogged pick-up or the pumps on its way out but they typically aren't intermittent. Also assuming you replaced the filter as well.

 

it had the correct amount of oil in it, when i drained it, it had the same amount in the drain bucket as it did normally, after i changed the oil, the next morning it was back to listening to the lifters and rollers tick, me and my father are going to change the pump in it

 

oh and i did change the filter when i changed the oil, i wont change the oil with out changing the filter

 

Tow the car in to get it tested to see if it is a bad pump or whatever.