Buy yourself a fault code reader or better still a PC based system so that your can look at the live readings from the engine as it is running.
http://www.gendan.co.uk/index.php
Warning lights usually come on for a good reason, just resetting them and sending you on your way sounds dodgy.
I doubt if the grade of petrol was cause a warning light.
Modern ECU system are pretty clever, I don't think you have a fueling problem other than that instigated by the ECU to protect the engine after detecting a fault (limp home/safe mode).
How do you know it was running lean? (the first thing most people notice is a melted piston!)
