I was on my way to work this morning when my '96 C280 started running very rough. Made it the rest of the way to work and scanned for codes, the only thing noted was a "misfire in cylinder 6 detected". Got home this evening, changed plug wires (all of them) and installed new Bosch copper plugs. Figured it was time as both of those items had over 90K miles on them. Still running rough, still detecting misfire in cylinder #6. If the #6 coil was going bad, wouldn't it affect #1 cylinder as well? I am open to any suggestions.

'96 is in the rotten harness phase of MB. Have you changed yours ?

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

a coil can affect only one plug,just replaced all of mine,bought 3 new coil Bosch for $59 each on Ebay

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

Did you change the plug boots on the coils? ( 3 of them )

Swap the # 6 coil for another cylinder and retest.

Coils can fail on both ends. This car has a waste spark system with a spark plug is on each end of the secondary winding. If one end opens up, both plugs won't spark. If one end is arcing to ground, the other end will still fire.

96 should have the good wiring harness.

I pull injector wires to test for a dead cylinder, however my 97 SFI ME 2.X it detects a miss fire then shuts off that cylinders injector. So, if you have a sometimes firing cylinder, it will go 100% dead after 15 sec and won't refire until the key is cycled.

I think your 96 has a older HFM system (2 or 3 ECM plugs Vs the 7 or so for 97 ) so it might not have cylinder shut down.

Lastly, there are 2 different coils for the M104 motor with the split sort of being 96 older HFM / 97 newer ME but the C class seems to have older coil overlap past 97 and the 4 cylinder gets mixed in too. Physically they look the same, I'm guessing it is a winding resistance change.

OK, so after I got home from work today, I moved the coil from #6 to cylinder #2. Fortunately, the misfire code followed the moving coil. I will get one in the morning and replace the defective coil. Hopefully that will take care of the misfire issue.