Strange Oil Pressure Problem

[shäferhunde]

I'm taking my '03 3.0 in to the local independent on Wednesday for this, but I thought I'd run it past you guys first. I've read through all the oil pressure threads I can find but don't see an obvious answer.

The problem is that I'm getting the flickering red oil light and the stop engine warning, but only after I let the car idle while in park for about ten minutes (the car was already at temp before the 10 min idle each time this has happened). After that, I'll get the flickering light when I put it in drive or reverse at idle. Of course when I accelerate or put it in neutral, the light goes out as you'd expect. The strange thing is that after driving a few blocks, the problem slowly goes away (first red light, the light will flicker a bit, second one a bit less, etc.) and won't reappear unless I park the car again and let it idle for another ten minutes.

I don't know of anything that would "re-pressurize" the system with driving, so I'm thinking that it has to be temperature related. The temp needle doesn't move when idling, so I assume that it's not the oil thats getting hot and thinning out. Outside temp has been around 80 when this happens, so not unusual. My best guess is that the ambient air around the pressure sensor gets hotter when the car is sitting and is causing it to fail. Then as I drive it cools down and starts working. Seems far fetched, but that's all I've got.

The car has been well maintained - a bit less than 100k miles and regular oil changes with Mobil 1, always do whatever maintenance is recommended, etc. I had the gasket on the oil filter housing replaced in December, but that's the only oil related work that's been done. I've got a small leak in the valve cover gasket but nothing major - oil level is good, filter is clean. Idles smooth and no engine noise or anything.

I also have no idea if this is something new or not, since it's only by chance that over the past few weeks I've found myself twice sitting in the parking lot of the grocery store while my wife ran in to get something. It could be a ten year old problem for all I know.

Any thoughts before I take the car in?