rdr1962

My 84 944 starts and runs perfect. EXCEPT, when you rev it up, and its smooth doing that, when you let off the accelerator it comes down past normal idle almost stalling for an instant before coming back to normal idle speed. It's an auto and when you are coasting to a stop with your foot off the gas, it will idle below normal and back repeatedly, 4-5 times in a row. Could this be the throttle pos. sensor? Can't find any vacuum leaks. I appreciate any ideas.