BrianE

I recently changed out the spark plugs with Bosch Double Platinum in my 2010 E350 and since that change my engine has intermittent rough idle and is causing my check engine light to come on. I hooked my scanner up to it and it's showing running rich in both banks. I tried disconnecting the positive terminal on the battery for several hours plus cleaning my K&N filter and it's still doing the same. Could the new plugs be causing this? I did notice that the idle started to run a little rough intermittently before the spark plug change, but since the change it has gotten worse. Could this be the sign of a bad coil pack? Thanks in advance for any replies.

Brian