Couguers advice (gas tank relief valve may stuck) above maybe worth checking and as mentioned here and on another Subaru website referenced checking the Charcoal Filter and Small Return Line on the gas filter to see if it is blocked and flowing freely.
Also as noted on Legacygt.com, "These later cars do not suffer from vapor lock. When the car is running, so is the fuel pump. Fuel is always circulating thru the system and back to the tank. Pressure is 34psi, and 60psi with the return line pinched. If not within these specs, you could have a faulty fuel regulator. Check all your vacuum lines and check the temp sensor with an ohmeter. Steven." May also be a good option to check.
Thanks everyone for the help and more info soon. Sorli...
Typical vapor lock in the fuel line is pretty much uncommon with fuel injected vehicles if everything is working properly
Have you tried the "opening the gas cap & relieving pressure" trick more than once? Does doing that work every time?
Edited by sorli, 09 June 2013 - 10:10 AM.