Hey gang, appreciate the last hand you gave on the vacuum pump it bit the dust. WHICH leads in to this saga (any 300SD's out there lemons???? )Well after the new vacuum pump is replaced it shifted smoother, less black smoke better pick up. After a 200 mile trip then it happened. It started to run with less power off and on then the engine would idle up fast and car was hard to stop, then it would shudder and barely stay idling. Then at a rest stop it would crank and feel like it wants to start but won't! Thought primary screen was clogged it had rust looking gunk yech! replaced it, still no good. What ya'll think bad diesel? Timing chain gone, this is a new one for me I am clueless and about ready to give up on MB. This is not a spare car that can wait around it on the go getting grand kids. APologize for this book, but thank you for your patience, expertise and help. LH Look forward to a hint, clue.....