When I am using more rpm, or letting it go back towards lower rpm. The car has a very large shake/ buzzy rattle that can be felt in the dash, and interior. So it happens when the rpm change occurs. In the driveway, or on the road- it is exactly the same... It has all new mounts, and the engine is running, and driving fine. Is this just how a trabi is? Maybe the fan has a chipped blade- knocking it off balance?