P0440 code + trouble filling gas
 

I'm trying to knock down my CEL's before april, when I have to get emissions. The only code I have left is the P0440 code. I'm guessing it's related, but I had trouble the last time getting gas. The pump kept stopping everytime it started to flow. I'm guessing this is a bad gas valve. if it is, do you have a part number, and instructions on replacement?

car in question is a rust free, 2001 4runner (223k).

What's a gas valve? You have a vent line that goes from the upper filler neck to the tank, and a dobber probably built a nest in that.

vacuum switching valve.

I think the two might be unrelated actually. Your gas vapors don't vent to your EVAP can while filling up, the vent line I described does. It sounds like it's at least partially clogged. It's pretty easy to pull off blow thru it. The PO440 is evap related, but could be something as simple as a bad seal on your gas cap, or you not tightening it down until it clicks.