I recently purchased an Audi A4 2009 as a second car. The belt, and the oil burning problem were already taken care of on the car before purchase, as well as the car taken to the Audi Dealership for inspection, came back clean, except to replace air filter for interior. However, occasionally, there is a burning smell when turning off the engine. This does not occur all the time, only occasionally, and does not seem to coincide with drive time. Any ideas? Thanks.