service engine soon light comes on but car diagnosed showed nothing wrong

is it time for a oil /filter change???

Did all that last week and reset change oil

Make sure that your tire pressure is accurate in all 4 tires and in the spare tire. Also make sure your gas cap has a good seal. These seals deteriorate over time, and you may simply need a new gad cap.

Also, some cars have a sequence of actions such as turning the car off, switching the key out of lock position, but not cranking, then pressing other buttons. Usually a certified mechanic would do this after servicing the vehicle for you. If you performed the service yourself, you can look up the key sequence in your auto manual where it talks about warning lights. If you don't have the manual, just call a service person at your vehicles dealer and they will walk you through this by phone. Then if it won't go out, you know you need to take it to the dealership or a certified mechanic to have the problem diagnosed.

Also, if the air filter wasn't checked and/or changed, you might try replacing the air filter.