I got had the same proble in my 2004 forester xt automatic. Also de engine light was on for about a half a year. The car would first hesite a lot to accelerate and a couple a day ago did not accelerate up a hill. my local mechanice say it could be two thing the flow meter (sensor next to airfliter) or the trotlee sensor. To check the flowmeter it is very easy just disconect the plug. I did it and the car runs prefectly so I know it is the flowmeter also I had a p0107 code before. If the probleme is still presente it is the trotle sensor

I had the same problem in my 2004 Forester xt automatic. Also the engine light was on for about a half a year. The car would first hesitate a lot to accelerate and a couple a day ago did not accelerate up a hill. My local mechanic said it could be two things: the flow meter (sensor next to airfliter) or the throttle sensor. To check the flowmeter it is very easy, just disconect the plug. I did it and the car runs prefectly so I know it is the flowmeter. Also, I had a p0107 code before. If the problem is still present, it is the throttle sensor.