Try cleaning and lubricating all of the ball studs and sockets along the throttle linkage. Use AFT or light hydraulic oil to lube. Should be cleaned and lubed at every other service or so.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.