i have a 1997 audi a4 1.8t quattro...when I ever start driving about 10 minutes later the oil pressure light comes on...then i turns off after a couple of seconds..i was wondering what the problem is...and also i have a small oil leak

 

Might want to see if the sensor is bad, it is the one at the oil/coolant exchanger. Could just be a bad wire. If everthing is good then you might want to install a aftermarket oil pressure gauge/sender so you can see if it is actually low. Pressure has to be well below 25 psi to cause the light to come on and 25psi is about what our cars run at idle when the car is warm.