Hi everybody, i have a 98 Audi A4 1.8t Quattro, whenever i come to a stop light my RPM stick dips and the engine thuds. Only when it is in drive, it does not do this in neutral. When the RPM stick dips and the engine thuds it shakes the car and it does this every 2 seconds. There is no check engine light so i dont know what the problem could be. Someone told me there could be a leak where the intercooler Sits. But i dont know. Anybody have any suggestions? please help me out!