clutch slipping?

[Milehigh30]

it doesnt happen often. but occasionally when i havent driven the car for a couple days or so i will be driving and i will completely loose all rpms. the car is still on just zero rpm. i can sometimes gas it and it will catch again. or go to a different gear and it seems to happen in 3rd. 87 325i

[808e30325i]

If it were the clutch slipping your rpm's would be going in the other direction.