Well, unclick the fuel line again and see what the orings look like. Maybe take it off and put it back on to see if the seals good.

And they make a core tool to remove the pressure release valve, a new one can be installed if needed. Perhaps it's just loose.

As for the misfire make sure you know what cylinder is really where. The front bank is 1,3,5 and the rear is 2,4,6.