Just bought the 944 a week ago. Was warmed up when I took it on a roadtest. Ran great! Next day took it out and it cut out around 1800 rpm. It got better as the engine warmed up. (higher rpm). when at full operating temp it ran great. Now it wont go over 1900 rpm. Any thoughts? Replaced plugs twice, checked coil, cleaned throttle body,cheched hoses and for vacum leaks