I am experiencing the same from the hosing towards the fuel injector in my 01 Outback. I tightened the clamps and that worked temporarily. Upon analysis from my mechanic they could not find anything. The condition started when I filled the gas tank to the brim You could try releving the gas cap. I read about vapor trap as a possible cause. I checked the air filter and that area had no residual effects. No obvious gas spill markings were observed in the engine compartment. Right now I am using Gumout fuel injector cleaner. If this problem continues I plan to contact Subaru direct If one of their people reads this we both would appreciate a solution. Gas smell and or leakage is big time worry. Their US corporate facility is located in Cherry Hill, NJ. If you have some luck pass it on
Philo from NJ FYI If you ever have a major head gasket problem Subaru owes up for that and will compensate when you submit your records and contact their excellent staff. Subaru brake systems do suck