what kind of vehicle?
check throtle position sensor and look around throtle body to see if something came loose or un hooked sometimes throtle cable will turn lose.
You may also have a build-up of carbon on the throttle body area which can cause the butterfly to stick and malfunction. Also check to see if there are any visible issues with the throttle cable as Papa suggested.
Looking for a Used A4 in your area?
CarGurus has 11,458 nationwide A4 listings starting at $800.
Search Audi A4 Questions
Audi A4 Experts