Well I tried a few more things...
1. I disconnected the vent line at the charcoal canister to eliminate the possibility that it might be plugged... NO GO
2. I blew out the main vent line with air, got some junk out. I then blew out the two vent lines from each tank (the T into the main line going to the front right next to the tank switching valve). Funny thing is that when I blew out the line going into my malfunctioning tank (the only one in service right now), it blew a ton of fuel out the filler, which I thought strange. Anyway STILL NO GO
So at this point I think I need to drop the tank. My thought is this: in this picture you can see the three outlets (supply, return, and vent). Below one of those lines is what looks to be a valve of some kind (hanging into the tank). For those who have torn one of these apart before is that a pressure release valve? Could it be that that is blocked up and unable to open? I am thinking that this may be my problem, because I can think of nothing else it could be!
You must be registered for see images