Cops

[walela1]

I described a vibration problem in my 04 black MM in a post entitled Shudders. The problem seems to be with cylinder # 4, ( if that is the second one from the engine front, passenger side.)

When I took the coil cover off that side, the Granatelli cops were discolored on their tops as compared to the normal looking ones drivers side. Checking each coil by pulling it off of its respective spark plug, that well the plug and boot sits in was discolored as compared to the other seven, kinda gray sooty instead of shiny in the well and matte aluminum up where the cop sits.

With the engine running, there was a tapping noise and an associated vibration could be felt by placing my fingertips on the coil top. This was not resolved by replacing that one cop for one of my OEM ones,(after remembering to change the lead polarity in the cop connector first,) nor was the condition changed by changing the remaining seven coils for the OEM ones.

Before I changed out he suspect GMS coil, I pulled it off the plug while the engine was still running and there was spark. I haven't driven the car since the coil r and r, but that tapping worries me and has me wondering if that sound is a valve slapping or worse.
:help:

[JACook]

Check that your spark plugs are still tight. Do it now. If any are loose, it won't
take much time before they blow out, stripping the heads in the process.

The spark plugs need to be torqued to 7-15 ft/lb. Few ft/lb torque wrenches are
accurate enough at that light a setting, so I use an in/lb torque wrench set to 135.

If you find any that are loose, pull them out, clean the threads, then apply a very
light coating of anti-seize on the threads, and a thin wipe on the taper seat. When
you torque the plugs, it's gonna seem like you're barely snugging them. Resist the
urge to give 'em just a bit more twist for good measure. If they're torqued right,
they won't loosen, and more importantly, they won't blow out.

[Blk Mamba]

What he said. ^^^^^^^

[walela1]

Kudos and beans to both respondents, the cylinder in question did have a loose plug, I did as advised as well as checking the remaining seven. No other loose plugs.

Problem resolved, when the NGK TR-55 set of plugs arrive, they will be installed next weekend. The plug in I did pull looked good, stupid me for not recognizing blow-by in the spark plug well, live and learn. Bless forums like these and the Internet.

Michael:beer: