Slow Return To Idle

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Mazda Tribute, 2002 Mazda Protege5, 2002 Mazda Protege, 2002 Mazda Millenia, and 2002 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

Check for Engine Coolant Temperature (ECT) sensor malfunction.
Check for intake air system leak.
Check for thermostat malfunction (stuck open).
Check for throttle body malfunction.
Check for throttle linkage malfunction.
Check for vacuum leaks.