ahweber03

Recently I was doing a bit of preventative maintenance on my 2007 C230 Sport (2.5L V6). I changed the spark plugs about 2-3 weeks ago, and my car started misfiring a few days ago. It was so bad I couldn't drive home, I called AAA and they towed my car to a local shop I trust. I received a call from them saying that the spark plugs were installed correctly, but I had 4 cylinders misfiring. They wanted to charge me $1200 to replace the coils (which is what they suspected the issue would be), so I had the vehicle towed back to my house where today I replaced the coils on my own. The misfire was just as bad as it was before with the new coils in. I ended up taking them out and putting the old ones back in so I could return the new ones. I did have a CEL for the PCM, which is the only other thing I can think it may be. The car is undriveable. Thoughts?

khomer2

Scan and post your saved codes here.

chassis

Pull off the following connectors and use a bright light to inspect for presence of oil:

- cam position sensors (4)
- cam magnets (4)
- ECU (1 or 2)
- O2 sensors (2 or 4)

So 11-14 connectors in total. Any oil on the connector pins could lead to misfire. Search this site for “oil in harness”.

E55Greasemonkey

Did you use oem plugs or some cheap crap from your local auto parts store?

khomer2

Let's make this a loooooong whack-a-mole thread, while the OP ponders his next step.