i have a stick shift car and when ever i take it out of gear for a stop or shift the rpms will hold at about 1500 for a fews seconds then drop down? what could be causeing this? it just stared doin this, before it would rev right down to 900?

 

When the car is moving, the PCM holds a higher idle speed. It won't settle down to the normal idle speed (800rpm for the M6) until the vehicle has fully stopped.

If you feel it's higher than it was before, check the throttle cable and the blades to make sure it's returning to fully closed when you release the pedal.