Hi there i have an a4 1995 1.8. When the car is cold and idling it runs fine at 1200 rpm. When it warms up the rev counter goes from about 1200 rpm down to about 600 rpm and up and down for 20 /30 secounds and then levels out at 850 rpm. Not sure what to do so any help will be gratefully appreciated. Many thanks from ade

 

sounds pretty normal...when it's cold the motor is supposed to start up at a high RPM until the thermostat opens up and then the rpms drop...

this is how most newer cars function....doesnt sound like you have anything to worry about

 

yep, normal...

 

It's normal. If its real cold out the rpms will stay around 800.

If you have problems with rpm bounce after warm up the coolant temp sensor may be bad. ($20 + 10min to fix)