On my way home form vacation last week I was driving down I95 and my daughter mentioned the engine in the '95 E300 sounded loud.

Shortly afterwards I pulled off on exit and it sounded really loud and diesel-ly, link a cold semi truck.

The idle was very rough, black and Smokey and it was a pain to start.
We drove the next 300 miles home and after looking for all the usual things like clogged filters, air leaks, stuck egr valve, or a blocked exhaust.
I was at the end of my rope as to why it started doing this all of a sudden.

Just for kicks I pulled the valve cover (and noticed the previous owner had left me a few broken glow plugs, ouch) and checked the cam timing.
To my amazement it was at 20 degrees before top dead center.
I triple checked it to make sure and looked for reasons why this could have happened.
The chain is not slack and there are no loose or broken components that I can find. If there was I'm sure there would have been a catastrophic failure during the drive home.

So it is easy enough to unbolt the timing gear from the cam and re-set the timing but without understanding what happened I don't know if it will happen again.

Does anyone have a clue?
Maybe this has happened to someone else?

__________________
'82 300D - Light Ivory, 2nd Owner (Back in the wind April 2013!)

'95 E300D - White, grey interior. (Suffering from stuck/broken glow plugs)

Deuteronomy 22:4-
"Thou shalt not see thy brother's ass or his ox fall down by the way, and hide thyself from them: thou shalt surely help him to lift them up again."