I've got a 99 forester with a 2.5 sohc that started acting up. It started sputtering and popping while I was driving it and no codes showed up. When it does it I can mash the peddle to the floor and it takes off. So I guessed and put a new fuel pump in her, but the same condition is still present. Funny thing is it's idling fine and when you give it some throttle it responds. It's only when I'm driving at lower Rpm between 1500 and 3000.