'89 volkswagen jetta. I have read many of the problems already posted, some seem very similar but I didnt read anything that I felt was the exact problem I am experiencing. The engine speed will droop well below the intended 800 RPM after depressing the clutch when returning to idle. The speed will droop as low as 600 RPM, at which point the engine starts to stumble and die before recovering and overshooting to 1000 RPM and then returning to the standard 800 RPM idle speed. This problem happens almost every time the car returns to idle. Please let me know what you think is causing this to happen.