If you have nav, there's an option somewhere in the maintenence option to change the mileage duration between oil changes. Was that messed with? That wouldn't effect the CEL and rough start though.
'02 GS300 Sport Design | Graphite Gray (SOLD)
'06 IS250 | Matador Red (SOLD)
'08 IS350 | Tungsten Pearl (SOLD)
'11 Audi S4 | Meteor Gray on Lunar Silver/Black, DSG. Titanium Package.