i bought a CPO 08 S550 last year the car has been great but i have noticed latly that when car sits few a few days there is a hesitation when starting. now i noticed that the car will not start right up if it has been parked for a short time when its hot i load tested battery with a good load tester and it held 300 amps at 8 volts does anyone have a sugestion on what way to go with this