Yup, it could take hundreds of miles for the computer to adapt. Try shutting off the check engine light if possible then drive it and see what happens...

Recently, my 2002 VW Passat had a check engine code for emissions. My mechanic shut off the check engine light (I really need to get a scanner for that car...:). Then I went to get the car inspected (emissions analysis is required in Mass for all cars 15 years old or newer). The inspection station couldn't do it. The inspector told me that with some cars it can take hundreds of miles for the computer to clear and readjust. After driving for a week or so I went back (check engine light did not return) and the car passed! Check engine light has NOT returned!