Plug connectors are a supressor resistor ..there are 3 are under the coils.
[ one each]
Plug wire boots are at the end of the ignition wires at the coil end of the wire and are just a wire terminal/plug with a protective boot over the terminal ..there are NO resistor/Supressors in this boot/plug.. The resistor connectors for those 3 ignition wires is at the other end of this ignition wire
[ plug end]
The 3 connectors under the coils have NO Ignition wires ..only a resistor /connector.
.. ..so, there are only 3 Ignition Wires on a 104 waste spark ignition system, but all plugs get the resistor/suppressor...either in the connector under the coil or at the plug end of an ignition wire.

So, why do we always recommend changing the connectors under the coils.??? B/C they have a high fail rate due to 2 factors ..one is the are trapped in engine and coil heat and the other is they have a friction type commpression spring connection to the plug by design. Two things resistors do not like are heat and poor connections.
The resistors on the other plugs do not have these condition b/c they are not heat trapped and they have positive snap design connector..so, very seldom will one see a failure on them, but you frequently see failure on the ones under the coils..so much so that any tech familiar with these will just change them automatically when doing a plug change...
... the high percentage of 104 misfires are caused by these coil over plug connectors, along with incorrect plugs installed , specially Plats... these engine like the large electrode of the copper core standard plug b/c they are a series circuit of two plugs fired with one coil...meaning the first plug fires from the electrode to ground , but the second plug, being a series circuit, fires from ground to the electode and then back to the coil..completeing the series circuit. Plat have a tiny electrode and that may contribute to their mis-fire rate in waste spark systems like the 104 has.

i'm gonna get the three end plugs and 6 new spark plugs just for good measure and then see if that solves the issue.

You DO NOT want the end plugs. These are incorrect part. They are the plugs on the end of the wires that go from the coil and feed the other plugs.. these are not the ones under the coils and are not the ones that cause the problem.
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=21Q1AKMTB21U0QIXGA&year=1995&make=MB&model=E-320-004&category=F&part=Ignition+Wire+End+Plug

The parts you do want are the coil to plug connectors [ 3 of them]. No wires , no ends ..just a direct connector/resistor. PLUG to COIL. Nothing else.
This is the CORRECT part.

http://catalog.worldpac.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=21H0MN3YU22W14AGMI&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1995&product=F1010-84561&application=000357359

Dang. I wish I had read your post earlier. I was Just about to post the question, "Where do these things go?!" I suppose I have to return them and get the correct part.

Yeah, Sorry, but I posted it as soon as I saw that post link you to the incorrect parts.. I was actually surprised..

Get the correct coil/plug connectors b/c the ones you got will do nothing to solve your problem.

THESE are the ones you want...3 of them... and they are UNDER each coil. Better Luck this time......

http://catalog.worldpac.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=21H0MN3YU22W14AGMI&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1995&product=F1010-84561&application=000357359

I like how someone mentioned the spark plug boots being soaked with oil ,and they replaced the valve cover gasket.

Good point!

I see tons of those circular o-rings that seal the valve cover gasket to the head, and they leak into the spark plug holes causing misfires from time to time.

I like to get a rag and hold it over the spark plug hole and blow compressed air into the holes (before) removing the spark plugs.
This will blow out any oil or crust and dust that has collected around the spark plug.
That way when you pull the plug, you will not dump a bunch of junk into the cyllinder.

Has anyone tried to drill a few holes in the lid to release the heat? Or would just a few holes make some harm to the system, I mean you can cover them when cleaning the engine?

__________________
-94 E 36 AMG Coupé, Brilliant Silver
-98 G 500, Obsidian Black
-05 Mini Cooper, Solid Black
-97 993 Carrera S, Ocean Blue

Te heat is trapped by the coil being over the plug , not the valve cover top.

well said arthur.

__________________
David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg