When I press on the gas hard and really get into it the stick shifter (AUTOMATIC) jerks a little and or moves back a little. What could that be?
Either engine mounts or transmission mounts. I bought a 2003 CLK with 22K miles on it. The engine mounts were shot and the engine was resting on the frame. so they do wear out with age, not necessarily use. If you have a good garage that can be trusted, have them put the car on a rack and have them show you if the engine or transmission mounts are good or bad.
Search Mercedes-Benz CLK-Class Questions
Mercedes-Benz CLK-Class Experts