1998.5 Audi A4 2.8L Quattro 83k miles:
The oil pressure warning appears when the weather is warm (over 65 degress); never happens during the winter months. When the oil temp goes above 225 degrees, the warning appears. This usually appears when I am idling in traffic and it disappears when I start driving. The warning light becomes more frequent when it gets hot and humid in Chicago and I have the air conditioner running. My oil level is correct and this appears even after an oil change. What is causing this?