Oil pressure light started coming on last week. Only comes on after driving for about 10 minutes then slow to stop and RPM goes below 1000. Oil level was less than a quart low, changed oil and filter...no change. 133K miles, runs well, 26 mpg, drive it 100 miles each day going back and forth to work. I'm thinking pressure switch but don't know where it is.

Anybody have a better answer?

 

You are not the only one. It seems to also happen on the 1g 2.5l. I have been adding long life oil (designed for high mileage engines) and it has seemed to help the issue. This oil helps to swell the gaskets to seal off anything that has loosened up over the years. I believe it to be due to engine age, things loosening up and gaskets, rings, etc wearing down.