i Need Help My s500 1997 w140 Engine is Shaking i think i need spark plugs

I drag it home on a trailer, a stipulation on the sale was that the car "does not run", I do believe as I was told that, somewhat emphatically, there should have been exclamation points, as someone who has been a mechanic on clunky junky cars for a very long time, you learn how to fix what breaks, and one day there came an opportunity to actually get a first edition w140, 99.44 percent intact, original.
Maybe it is some sort of macabre forensic mechanical examination process that has happened, or this car is so mechanically refined it may actually be possessed, any number of possibilities come to mind.
A visit to a number of junkyards found a lot of parts, fuel pumps, fuel lines, blower motor and regulator, trim parts, cigarette lighters, fuel cap.
An adventure in automotive restoration has begun, in three months, I have spent about sixty dollars for parts, all the vehicle is there, it has layers of dirt, grease and needs a thorough going over through and around.
For Mercedes Benz to actually spend a Billion dollars on this model vehicle in the development stage, wow! It sure must have been something fantastic that they envisioned it to be as the final product.
I am doing a forensically correct rebuild of my car, there are very few machines that can duplicate the performance characteristics of a w140, sure, they were built with some built in parts that were not quite up to the expectations, over time, the problems show themselves, a very powerful and amazing automobile, in its time, even to this day.
for the past few weeks I have been having a couple of cylinders that have a really weak spark, the engine has at least two cylinders that scarcely fire at all, I cleaned out a layer of green corrosion from under the distributor caps, using fine sandpaper to shine the contacts, I found one of the primary coil wires pinched under the air conditioner condenser tank, from the factory assembly, the spark at the distributor cap is nothing short of portable lightning once I got that untangled, Wow!
I am going to try and find out if the spark plug wires are bad, or if the problem is in the distributor caps, there is a black plastic cover over the orange color distributor cap that I cannot figure out how to remove without breaking it, the oil and grease and arcing and sparking happened as I was trying to go through the firing order trying to find the "miss" in the engine, by disconnecting one spark plug wire at a time, there seemed to be a lot going on under the plastic cover.
I do not yet know where the source is for the ignition coils to receive their information from, but it appears that this missing spark iis a common problem for many of these vehicles.
I will be following this thread to see what we can find out.
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I have the same problem with my s500. Its the centre bearing on the drive shaft.
Would recommend replacing the bearing and have the drive shaft re-balanced.
Well it's now happened to me - missing on at least 1 cylinder but feels like 2.
Drove it home thinking about new plugs, wires, coil packs. With only 70,000 kms and from what i've read on here- I think probably it's a good idea to replace the lot and do it once... (the shaking at stop lights, the underpowered run down the highway - just started it doing it for first time ever on a day that's +10 C and saw the engine running at temperature down the highway.
Notably the shop would have likely had the covers off recently in December when they did some gasket work for me - wonder if they wiggled something or if it wasn't put back - I"ll check under my black plastic cap..... Any other thoughts?




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