Having a heck of a time still with COP's going bad. I just recently replaced all of them twice! It seems as if cylinder #4 keeps getting water or maybe coolant in it if that's possible? I thought it was water, so I RTV'd the crap out of the cover where the rubber grommet is at and it still got water in it somehow and causes it to miss and stumble. So my question is can coolant leak into the spark plug hole? I only thought oil could from the valve cover gaskets leaking. It's got 61,000 miles on it and I'm about sick of this thing.