Car is sluggish when I accelerate and sounds as if it is backfiring. What would

I am having the same exact problem with my '00 Outback. However I do not hear any backfiring.... it just feels like it is losing power when accelerating at lower speeds. Lurking, hesitation, weakness in being able to get up and go. Yes, the Check Engine light is also sputtering on and off. However the only thing this indicated when it was diagnosed was that it needed a new catalytic converter. Would a bad catalytic converter cause this issue... or would it be something else? In the colder months of the year... I have also smelled gas intermittently. Not a weak smell of gas... but a strong smell of gas... like you are sticking your nose in the tank when filling it.