what causes this problem
on the '85 300D with the throttle valve linkage? When I had the linkage disconnected and the car off I pulled on it and the resistance was slightly different at the end of the pull versus say the first 75%.
The only things I have done so far was insure that the Bowden cable is correctly set and I have changed the fluid and filter. When I dropped the pan to change the filter visually everything looked great - clean, no burnt smell, etc.