One problem related to car throttle sticking has been reported for the 1999 Audi A4. The most recently reported issues are listed below.
Audi A4 1999 2. 8 liter - throttle stick during cold weather when cruising at steady speed or when accelerating from rest. Drivers only recourse is to pull over and switch engine off, wait a period of time before restart. Identified as moisture freezing in throttle body. Note currently Audi a6 recall in place.