I am new to Audi. I have a 2006 Quattro Avant that I have owned for about three weeks. A couple of weeks ago it started throwing the P0171 code. I did the spray test of the vacuum system with carb cleaner but no response. I plan on doing a smoke test this weekend (it looks like the canister purge valve has been replaced). Tonight I drove home on the freeway with no incident until I pulled into my driveway and noticed the engine was running rough and surging. I pulled in the garage and put the car in park. The idle was surging from 600-1000 and running rough. I ran the codes and found the P0171 which I expected, but also found P0300, 301, 302, 303 and 304 (Misfires). I cleared the codes and let the car sit for an hour, started it again and it ran fine. I did notice that in neutral, my idle was about 1200. Not sure what is going on here.