Oil light intermittent on off on at idle or when driving at 2000Rpm, cause? Is the sending unit a possability?

It is possible that the low oil pressure when idling in your 94 Dodge Dakota 3.9 could be caused by either a faulty oil pump or a faulty oil pressure sending unit. It is difficult to accurately diagnose the issue without further information and a proper inspection.

Oil pressure sending unit/sensor is faulty. Replace it and no more problem.

You need to find out why you have low oil pressure. It is normal that as engine rpm's increase, the oil pressure will rise- the oil pump is moving oil faster. Even though your light goes out, you could still have critically low oil pressure. There should be sufficient pressure at idle to keep the light off. The light will come on when your oil pressure is almost nil- I believe for some it's as low as 8 psi. Normally, oil pressure at idle is specified anywhere from 15 to 40 psi. You would have to check specifications for your Expedition. To verify oil pressure, hook up a mechanical gauge at the oil pressure sending unit on the engine block. Check with a local shop.

The causes run from easy, simple to budget busting ruin. Low oil level, wrong grade oil, real old oil, oil leaks, internal oil leaks, worn oil pump, worn crankshaft bearings. It was pretty common on older very high mileage cars to have a fluttering oil light at stops and idle. It was time for a rebuild, or time to look for another car.

WHAT IS THE MILAGE??OIL CHANGED RECENTLY??WHAT SAE??RED OIL INDICATION ON??

i would suggest you change the oil pressure switch ,also called oil sending unit first. this part is not that much and isnt hard to do.if that doesnt fix it then you might have an oil pump going out

You mean the light shuts out the truck dosn;t stall right Yes then i would try replaceing the sending unit likely is the cause of the problem

The Oil light is a dreaded sight, especially at idle. Usually if an oil pump fails, it dies, the same with an oil pressure sender. I had the same problem with a 97 neon, at idle the oil light comes on... (192,000 miles). If the oil used at the oil change was a thinner viscosity than what was in there, that could cause it. If not, it could be bearings going bad on the motor creating a low pressure situation. I fixed it by going to a thicker viscosity, from 5w-30 to 10w-30, and in a week the light went off... this was 7 months ago. Just food for thought, hope this helps.

First, check the oil level. Make sure the oil is at the proper level. If it's OK, then there maybe an oil pump problem or the oil pressure sending unit problem.
A Mechanic with an oil pressure gauge will be able to determine if the oil pump is working correctly at idle or the oil pressure sensor is bad.

a bad oil press sending unit...

Oil light that comes on while in idle means the oil pump screen is clogged or damaged, cause low oil pressure to the engine. That part is only $30. It could be a bad oil pump though, if that is the case the pump can run you $100. Either way you need to get it fixed ASAP it can cause major damage to the engine in a very short period of time!