I started throwing a P0455 Evap Leak code. I checked all the hoses and they were fine. I also started experiencing hard starting after filling up the tank with gas. I started suspecting the evap purge valve.

I pulled mine off (easy - right next to the battery, 2 hoses and 1 electrical connector). I figured when powered off it should not allow air to flow through it. I sucked on the hose fitting labeled "vac" and it did allow air to flow. I took it apart and cleaned it to no avail. I just picked up a new one and it does not allow air to flow while powered off and appears to have resolved my problem.

I just thought I'd post this up for the next guy doing a search. If your hoses look good it's really easy to pull the evap purge valve off and test it by making sure it won't pass air by sucking on the hose fitting labeled "vac". The new part is $20.