The cover I'm referring to is on the outside of the timing cover. It's five bolts and rtv. The little seal between that cover and the spinning cam gear provides the hydraulic pressure to operate vtc.

 

See this post for a picture of what happened to mine: https://my350z.com/forum/showpost.php?p=10868312&postcount=54

 

Long story short i puf a new selenoid on the problem bank after testing to make sure it was getting the correct voltage signals and that fixed that issue. Turns out an oil squirter broke off(not enough piston clearance) and oil was blowing onto the sidwall. This was fouling the plug and eventually i got enough fuel in the oil that it thinned out and ended up just barely taking out the crank bearings.
...The z is down for a bit