I have a 2009 A4 with 16,300 miles. Last week the check engine symbol lit. I thought the car felt sluggish and was going through gas faster, but not sure. Three days later the light went out. A day later the passenger airbag malfunction lit up. Later that afternoon, when I got back in the car, it was out. Two days later, check engine back on. Could be unrelated, but weird goings on. I have an app't with dealer on Monday. I did not do the 15K service. I had my regular mechanic do the oil change and rotate my tires, that's it. So the service indicator still comes on when I start the car. Dealer said they would reset that for me too.

Any ideas, without knowing the code?