Subaru Repair: 2006 Baha, timing belt tensioner, vacuum gauge

Question
From the moment I drove my brand new Baha off the lot, it has had this problem. When I accelerate in first gear, the engine falters momentarily, and sometimes stalls out. It hesitates under acceleration in higher gears a little, but the first gear is much worse. I took it back to the dealer, and they replaced a timing belt tensioner, but that didn't help. I've just returned from a 3300 mile trip, and putting miles on it didn't help; in fact, it's more noticeable now.
It's a 5 speed, and no turbo charger.
I called another dealer and was told they had similar issues with the Outback.
Any ideas before I return to my dealer?

Answer
We have had a couple of Outbacks that had one or more intake valves that were adjusted to tight from the factory causing a rough run.We noticed all of the symptoms you have but it was also rough at idle.Using a vacuum gauge we could see unstable vacuum readings.We than used a ultrasonic tester that we installed in the tail pipe which showed us one pulse in the combustion process for all cylinders was weaker than the other.I doubt that the dealer employs this new technology.Anyways i hope this helps and stay the course no matter how frustrating it gets
as when it is fixed and running properly it will be a great car for you.

Justin
All Wheel Drive Auto