I assume you're talking about the center spring loaded push rod, rather than the long rod used to prop the hood open. I managed to eliminate the hood shake by adding more rubber buffers at the back, and getting the front ones quite tight; plus added a drop of oil to the push rod where it goes through the brackets.
However, a friend opened up the holes in the brackets and inserted nylon bushings, which is a more complete solution IMO. If it becomes an issue again, I'm going to try that.