I fear the worst (bearings) because this car has overheated a couple of times, but I have seen this light come on before.

The key is that it runs pretty good when cold and for short trips in city. Once I drive 45mph or more for any length of time over 5 minutes, I get the oil pressure warning light at idle, and the car is sluggish.

I changed to a much thinner oil recently and suspect that as the problem--it happened once before after an oil change. I am first going to flush it and then refill. I may take off the pan but haven't ordered a gasket and want to test my theory first.

Thoughts?