Hello all, I'm a new member as I figured I could learn a thing or two and get help with what is wrong with my Expedition. I have a 2002 Expedition 4x4 5.4L with about 355,000 miles. A couple of months ago, it would run fine until you would get to an idle while in drive such as at a red light or in a parking lot it would start to shake and almost stall, but besides that it would be fine. Well last week we were on our way to Atlanta for a Drs appointment on the interstate and the oil light came on and it started shaking so we pulled of the exit to a Meinekee where they checked it out and changed the oil. They said that it was black and gunked up.
​​​​​​​We had it towed home, and several people who came to see what they thought it was, said that it was the oil pump. When you crank it up, it runs fine for a second or so and then oil pressure drops and starts running rough. So 1. What do Yall think it is and ,2. If it is the oil pump, what is involved in changing it out. Thanks, and sorry for such a long post, just didn't want to leave anything out.!

 

Might be as simple as an air intake leak, check your pcv 90° elbow to see if its collapsing or has cracks. These oil pumps are rare to give out unless you neglected on changing the oil, then the pick up tube is getting blocked by sludge.

 

Are you sure the oil pressure drops, then it starts running rough?
If it starts running rough the oil pressure will drop.
Do you know what the oil pressure is at idle?
The oil pressure light or even newer "gauges" are just an indication the oil pressure is at least 7psi.
Have you checked the IAC?
Flush out the oil system.
Check for a vacuum leak particularly the PCV and intake manifold as those can cause a leak bad enough to stall an engine.