I've been a long time lurker while I've been sorting through my new to me '97 S500 (my first M-B - I'm a BMW guy).

I've been on a quest to get this poor thing cleaned up and running reliably for a few months now. It just turned over 157k today and seems to more or less have been maintained over the years. While the idle quality is 99.99% better than it was when I started, it's still not as buttery smooth as I'd expect.

The car had a horribly violent idle initially with multiple misfire codes for cylinders 2, 3, and 4. It also had a horrible tick indicative of a blown oil tube.

Here's what I've done thus far:

- New correct plugs installed (had platinums originally)
- New MAF (old one tested marginal)
- Replaced oil tube on cylinder 2
- All injectors cleaned
- All coils known good
- Vacuum leak identified and repaired that was cause of misfires
- Motor flushed after replacement of oil tube (no indications of sludge but did in case cylinder 2 lifter might be gummed up).
- All pre and post cat O2 readings look OK
- New motor mounts and trans mount
- All systems tested with MB-Star
- All adaptations reset
- No codes whatsoever

The two biggest issues it seems were the vacuum leak that was causing the misfire codes and the completely collapsed motor mounts which actually appeared to be original (!?!). The new mounts made a huge difference with the idle quality, but there's still a little bit of oscillation at idle which increases slightly in gear. Zero issues with hesitation and it pulls very strong all the way to redline.

While it's perfectly acceptable now, I know it's not quite 100%. In my quest to find the root cause of my misfires, I did find a lot of discussion about timing chains, but I'm not convinced that would cause this particular issue. It's a very slight oscillation.

Anyone else been down a similar path? And thanks to all who have documented their own personal journeys over the years. It seems I'm not in minority in my quest to chase these vibrating gremlins out of my M119!