white99gt

I have an 06 C230 with 128k miles on it. About 10k miles ago, it started running rough and flashed the check engine light. It showed a misfire on 2 cylinders. I replaced the plugs and the old plugs had the ground strap bent over against the electrode. New plugs were installed and it ran great for a few weeks and went to missing again. I pulled the new plugs and some of them were done the same way as the old ones. I re-gapped them and on we went. When it started missing a third time, I bought a whole new set of coil packs. Replaced them and have still had a couple of plugs get the strap bent. I was getting misfire codes before, this time when I pulled the codes, it gave me a circuit fault on all the coils. Only other code I have is a cam over retarded, but I've heard that replacing the magnets fixes that one. Any ideas? Only thing I can come up with is maybe something in the harness for the coil packs or the computer.

Moviela

On the secondary where the piece extends into the hole, make sure it is hospital clean. You don't want arcing or corona to the head cover stealing your spark. Clean the bores too. Sometimes the gasket leaks oil into this area that fouls the high voltage for the plug.

I like to put a finger of dielectric grease on the plug top to allow the coil pack electrode to make good contact, and keep the connection air tight.

Check the connection between the car chassis and the motor/transmission to make sure they are clean and tight. Also follow the brown leads from the coil pack connectors to the ground point. Make sure this is clean and tight too.