First off, thanks to all who replied to my engine oil questions. I ended up buying the car because everything checked out and it passed smog well. It's a 2007 A4 Quattro 2.0T automatic.

However, the first night I took the car home, guess what - Check engine. I contacted the previous owner (she is very honest, and I do believe her) that the light was never on prevously. I believe her because when she smogged it at an Audi dealer on Monday, it passed. Even with a pending code, it would have failed. However, during the time of the smog, the dealer worked on a TSB for the ignition coils. I have to dig up the TSB #. I have a feeling that is not a coincidence. Here are the codes I scanned:
P0171 - Too lean
P0300 - Random/multiple misfires
P0301 - Cyl 1 misfire
P0302 - Cyl 2 misfire
P0303 - Cyl 3 misfire
P0304 - Cyl 4 misfire
P0441 - Charcoal canister

With the exception of the last one, it sounds like it's misfiring (although it seems to be running ok). Being new to the A4s, should I contact the same dealer and see if they'll look at it for free (which I highly doubt), or should I look for something in particular?

Thanks in advance.

 

If it's a bad coil it will be free. Maybe all the coils have not been changed from the recall.

 

So the recall # is J1/28F2. It appears that they replaced an ignition coil (or coils) and now I'm getting misfire DTCs. I am just worried they will try to pretend it's not a coincidence, and I'll have to pay for diagnostics and replacement. I could do the work myself if they try to pull that.

 

All coils need to be done. Ask them to run the vin and see what you have had done. When I had my first coil changed they only replaced the failed one and left the others in. I had another fail the next week and demanded they change the other 3.

 

They would have replaced all your coils....

p0171 is a vacuum leak..... which is causing your misfires.... typically from the breather valve on a 2.0

 

Thanks for everyone's help. It was the PCV valve, and replacing it fixed the issue. No more misfires and DTCs are all gone.