Check Engine Light On problems of the 2009 Audi A3

Purchased car in 2010 with around 10,000 miles on it. A few months after purchasing, check engine light would illuminate, vehicle would have a noticeable decrease in power and not accelerate over about 40mph. Sometimes after shutting car off and restarting problem would go away, other times it would not. Vehicle taken to Audi dealership car purchased from for repair and initially reported as sensor problem and repaired. Couple weeks after repair car would have same problem, so taken back to dealership and again repaired sensor(s). Within about the first year after purchasing, issue happened multiple (+/-5) times after dealership �repaired� what they thought was the problem at the particular time. After about 5/6 times of this happening dealership took a more in depth attempt at figuring out what problem really was, telling me they were working directly with Audi & their mechanics to find and fix the actual defect. Car was in shop for around 3 months for this repair, which they determined was electrical and decided to rewire the entire car. In the meantime, I moved out of state to start graduate school. I finally got it back a few months later after having to pay to ship it to me and for a rental while waiting. Within a few months, car once again had same exact problem. Took to new local dealership who also diagnosed issue as sensor(s) & �repaired� them. Continued to have same problem every few weeks, would take into dealer for repair, get it back, have problem, take to dealership, etc. Dealership would not address car overall being defective, they'd avoid contact, not return calls, hangup etc. Car eventually traded in for new make when warranty expired.