Help with hesitation at high RPMs - fuel starve?

[Austin David]

So .... after talking to Mr. KnifeySpooney and admiring his ITB setup, I left the little grommet off my valve cover.  Yesterday I decided to put it back because it was on my desk.  Today I went to start and ... didn't.  Rough start, turned and fired but didn't want to idle.  I babied it up into running ROUGH at a normal 1200rpm idle, stinking of fuel, and started diagnosing.  First step was removing that grommet.

 

It was fine by the time I had the cover off, but I did confirm that disconnecting any one plug reproduces the issue.  I could NOT make it misfire by smushing on the exposed #4 cyl wire, but I assume that was the problem.  Just took another little shakedown ride and everything was great.