I really would appreciate some help on this problem. I have 1997 Mercedes E300 naturally aspirated diesel. In the mornings when engine is cold it misses on one or two cylinders till it warms up about 5-10 minutes. It's not a fuel issue. I did the paper-over-tailpipe test and indeed it is sucking in during misfire. My current theory is lifters that won't squeeze down enough and is holding open the valves open. Could it be the valve itself is just sticking open because of sticky carbon deposits on shaft holding it open. I have been running WVO in this car and it makes no difference in the symptoms even when I switch back to straight diesel. It gets a little better on a fresh oil-change and 25 oz of stiction eliminator oil additive. Thanks Tyson

Run some steam through it from a wallpaper steamer or a kitchen cleaner steamer device .
Remove the pipe from intercooler where it joins the manifold and place the steam pipe facing upwards towards inlet about two inches below it and the engine can take the steam it can pull in and no large drops of water can go in as they fall to the ground . Run around 6-8 litres of water as steam doing this and you will unstick piston rings and anything else such as valve stems gunned up.
Run the engine at a fast tick over say around 1100 rpm and change oil afterwards although I always found this was not needed but if the engines breathing heavy then it’s best to do it.
Result will be engine runs much better and this should clear the problem up if it is not a mechanical issue.
Do this before every oil change if you run veg
Just realised you are non turbo so just rig the steam up in a similar fashion so it’s drawn in by engine rather than forced.

WVO gums up the fuel system and carbons up the engine real bad. Runs fine for a while then you start having problems such as this.

So I have a source of free Jet-A fuel (kerosene) to use. I ran car till almost empty and filled it up with 17 gallons of jet fuel. I plan on purging system completely and hopefully the extra heat of jet-A will burn off the residual deposits sticking to exhaust stems/valves. I'm purchasing 2 extra fuel filters to have on hand because the last time I did this with regular diesel, it broke free a bunch of crap and clogged up filter pretty fast. Any thoughts on whether this will work or not? Open to suggestions / comments.