I just thought that it might also be a bad coil wire.
You have 3 coil wires and 3 spark plug wires that pig-tail to the next cylinder. Each coil wire is responsible for two cylinders.
The resistance in MB wires is in the boot or end of the wire, just like Porsche and VW's.
It is usually the boot that goes bad, not the wire, and it is cheap to replace the boots - a couple of dollars for the three.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".