obdII does not always pick up. my wife has a 2000 vw bug turbo that once in a while it stalls when you come to a stop. and it does not code. the dealer just shakes his head. most likely the throttle sticks. by all means hook up the scanner.

2001 5sp. K&N stock filter 215/70/15
If your check engine light is on at least you know the light still works