1996 Jaguar XJ6 ACCELERATOR PEDAL STICKS?

WHEN I INITIALLY ACCELERATE FROM A STOP, MY PEDAL SEEMS TO STICK. IF I PRESS HARDER, IT WILL ENGAGE AND MOVEMENT IS QUICK RATHER THAN GRADUAL. i ALSO SEEM TO HAVE REMARKABLE COASTING, BECAUSE THE CAR DOES NOT SLOW DOWN WHEN I REMOVE MY FOOT FROM THE GAS PEDAL. THE RPM GAUGE DOES NOT GO BELOW 10 WHEN I AM STOPPED. HELP. WHERE DO I START.