[THEFERMANATOR]

Glad you got it figured out, I was at the race yesterday so I wasn't able to check in. Yes that rubber piece goes over the return line pipe on the bottom of the unit, and it sit's inside of a metal base on the inside of the tank to hold the assembly in place. If you don't have it in the metal base it WILL leak around that O-ring as it will not be square inside the hole. It will also cause the gas guage to give false readings on a regular basis. Sounds to me like you have a blockage that was caught inside your regulator as your fuel pressure should be roughly 30-32 at idle, and 38-40 at WOT.

I hope you dropped the tank when you did it, if you didn't it is nearly impossible to line up the return base inside the tank with that rubber stopper and drop it in. Learned this one the hard way. I didn't drop the tank and it ended up breaking the solder's on the metal tubes where they pass through the metal plate and had some MAJOR fuel leaks with a full tank. If your pressure was spiking to 50 then it wouldn't be a bad idea to check the inside of your regulator for trash.