Hi I have a 2001 subaru forester and yesterday I notice when I tried to start it, although it turned over fine it struggled to get started. I had the guys at work (mechanics) take a quick listen to how it sounded, and there guess is the battery because as far as they can tell it is they original. They are going to load test it for me today...

But I know Subaru's better than they do (not mechanically of course) and nothing is ever that simple...

On the way home I fueled up the car because I was down to 1/4 tank and low and behold the car starts beautifully!!!

Any ideas?

Could just be a battery. It could have a weak cel and start to discharge when sitting.