i have a 1997 audi a4 1.8t quattro when the car is warmed, heated up the oil pressure light comes on.....BUT ONLY ON 2.5 RPMS OR LOWER if i drive in higher rpms and gun it in stop signs and red lights it doesn't turn on..im in desperate need of help..thanks

 

You obviously checked your oil level (right?), so either your oil pressure sensor is bad or...

All I can say is AutoRX, Mobil 1 0w40 changing often and use high quality filters - I use Mobil 1 M1-301. If no go, you're looking at what could be an expensive repair.