Here we go, First Problem creeps up

[alm450]

After driving my 91 Mark VII around and burning up a bit of rubber something has started to happen.
My oil pressure light starts blinking at idle!
This only happens when engine is in normal operating temperature, and at idle at stop lights, signs etc. If I turn the steering wheel the rpms drop to 500 and light comes on almost steady.
Idle is about 750 when at a stop light, I've changed the oil (5W30), and checked it to make sure it wasn't burning oil and it isn't. The power steering fluid was a bit low so I topped it up, and it seems ok, other than the fluid being a bit murky.
I took a peek at the pcv valve and it still rattles, I didn't take out the screen, engine was kinda hot to be mucking around in there.
It doesn't do this when cold, only after it's been running for a while, and more often if I've taken it for a good speed run, It doesn't really do it on a leisurely ride home.
Any ideas?
Thanks

 

[94m5]

power sterring is a seperate sys and is a closed sys. sounds like you might be having the first signes of to much bearing clearance or could be a bad pressure sensor change it and see if that helps. it could be a loose electrical connecion. before you change sensors try using di electracl compound on it. what might be happening is it gets hot and opens the error message to the computer. just an old guys view. jd

 

[alm450]

Ok,
I'll check the oil pressure sensor.
But first, where is it located? My haynes manual doesn't mention anything about it.
Also the bearings you are talking about, oil pump?, cams?

 

[ILL VII]

The oil pressure switch (not the level sensor) is located on the drivers side of the block, right around the oil filter, it has a 90 degree elbow connection going to it. It also requries an oil pressure switch socket.

Looks like this, but you wont be able to see the threaded part, obviously.

 

[OldSchool1]

Could you repost that with a larger picture?

I can barely see it.

Thanks for the info !