2008 GTPHT; Each day on my initial start up, when I begin to back out of my garage my car 'hesitates' almost as if someone pulled the emergency brake. This is a rather recent development and sort of coincides with an check engine code indicating a loss of pressure in the fuel system. (Normal cause is gas cap not tightened.) I've replaced the cap, but the light comes back on after a day or so...Anyone have any idea what could be causing either of these two events (if not both)? It does fine after that initial backing. I allow the car to warm up, but after 4 years, this has just begun. Mileage is approaching 58K. I had the dealer check it but they reported "unknown code". Funny, but Advanced Auto and my neighborhood garage get the same reading every time. Could be that it is under warranty sill?