Check Engine Light

[Verdoro 68]

I believe those are knock sensor codes. My car threw them after a rodent ate through my wiring harness. It seems odd that you would throw them with no mods to the car. Take a look under the hood and make sure the harness is intact (rear of the intake manifold, wires run under the intake manifold to the sensors in the valley) and all the hoses are connected.

Based on your symptoms (running rough, bad milage) I bet there's a vacuum hose that has either worn through or came off. If you don't see anything out of the ordinary under the hood bring it by the dealer and let them have a look.