Did you change the three coil wire connectors?

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

This is the smaller wires? No; but was going to look at that next to see if the caps needed cleaning.

The three coil wire connectors are usually what cause a misfire. It is almost never the coil wires or the three high tension leads that piggy back to the next cylinder.

Search for posts by Arthur Dalton. He has posted frequently on misfire issues for your engine.

Here is one post:

"The wires can cause your problem, but they are the last place to look.
The problems with mis-fire on 104 Waste Spark ignitions is the connector/resistor UNDER the coil...that is just the way it is b/c they have an inferior connecting system and are heat trapped.
Any Tech will tell you to change them at a plug change b/c of their frequency of misfires.

So, that is the FIRST recommend , but not a diagnosis..it is a 'Change them regardless " recommendation b/c of their know failure rate.

And don't make the all too common mistake of moving the coils and watching the codes to move with the coil WITHOUT pulling the connector off the suspect coil..I see guys swap coils for that valid diagnostic trick , but they leave the connector on the coil they are swapping, not realiziing that it is the connector that is following the code . not the coil..
So , they buy a coil when all they needed in the first place was the connector under the offending coil."

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Since the car is at 197,000 miles I had no qualms about purchasing new spark plugs, the 3 'coil-to-spark plug' wires, and one new coil which came with the boot. Cylinder #5 is misfiring and it is not under the coil; it is connected via a spark plug wire, which is now new. So this connector 'under' the offending coil seems to have no bearing on my problem. However, if the wire lead connector on the opposite end from the spark plug wire connector on the new coil is bad, that could allow spark on the #2 cylinder but not allow it through to the #5 cylinder?

I have done tons of searches so far and not found one that seemed to apply directly to my situation. Usually see search results for no spark on any cylinder or replacing the coil fixes it, but neither apply here.

The high voltage path runs from one plug, through the coil connector, through the coil, through the wire, and to the other spark plug. So a bad plug connector can indeed affect spark quality on both plugs. The coil connectors only last so long. Folks who have been hanging around here long enough have learned to replace them every other set of plugs. Suggest you give it a shot. Shoot, they're not much more than 10 bucks each and only require 10 minutes to install.

If that doesn't fix it, then you've likely got a fuel problem on #5.

Still not sure what this 'coil connector' is. I've only got one cylinder misfiring, cylinder #5, and it isn't getting spark. No spark. And again, no spark. So while there may very well be a fuel problem, not sure how that applies to *no spark*.

If you are talking about the 'posts' that the coil sits on which connect to the spark plug under the coil, the new coil came with a boot. Still, I have some spares I ordered just in case so I'll try swapping them too.

The only item left that isn't new is the wires that supply energy to the coils.

If this was an older chevy engine I'd swear it was a cracked distributor cap. But that doesn't seem to apply to this car.

Thanks.

Coil wire boots that you are referring to are just a wire plug with a protective boot over the terminal. There are no resistor / supressors in this boot / plug.

The resistor connectors for these 3 ignition wires are at the other end of this ignition wire.

The parts you do want are the three (3) coil to plug connectors. No wires , no ends ..just a direct connector/resistor. PLUG to COIL. Nothing else.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".