I have a 1983 300SD, recently changed all fluids, new rack dampener, new motor mounts, etc. It has been running fine, then on my way to the gym the other day, it started running rough at idle out of the blue. It got to the point that I couldn't hardly accelerate at all and the engine would actually die if i didnt feather the throttle. Once you get the rpm's up, it runs fine. It also runs fine intermittently between the cut-off's. It will idle fine then out of nowhere start running really rough and quit sometimes. Any ideas/advice would be appreciated.