Need to watch what oil filters you use, Mpbil 1 and K&N 3001 are good, many will cause dry starts.
You may want to consider doing an engine flush to clean out any build up inside the engine,

 

I have no knocking. The car is running well aside from the light. The problem surfaced about 600 miles after my last oil change. The problem has been going on for the past 2 weeks. There are time when the light wont go on for a day or two bututlimately the light comes back on.

 

What year is your truck, how many miles?

 

I use MANN oil filters. It is a 2003 Discovery with 72,000 miles on it. Any thoughts you could offer would be appreciated.

 

I am concerned, 03's are known to have oil pump issues, many 03 engines failed before Rover went to a new design.
I would do an ATF flush this weekend, if that doesn't hel[ then you need to have an oil pressure test run both at idle and at 2000 rpm's and when cold as well as at operating temp.
Don't waist any time on this, I would hate to think you might have one of those pumps.

 

I'd stick an oil pressure gauge on it right away. Even a $20 unit will do. You gotta know what it is before you can make any meaningful assumptions.

Mark G

 

I put a gauge on it and it shows a hair over 6 psi when idling and when you accelerate it goes up. Any thoughts?

 

Might be time for a high-volume oil pump.

Mark G

 

I am not having much luck figuring this out. I had someone look at it today. They dropped the oil pan and said there was no metal fragmence and very little sludge in the pan. The pressure is still around 7psi at idle and running around 40 when reved. The mechanic said their is nothing suspission in how it is running and based on how it is running and how it sounds the only indication of someting wrong is light.
Anyone have any thought aside from putting a new engine in the disco?

 

Did the mechanic suggest replacing the oil pressure sender unit? It's a small and relatively cheap part to replace. If the light still comes on after replacing that, then the pressure is very likely too low, no matter what that mechanic says.

Can anyone confirm that 7psi at idle is normal?