http://www.obd-codes.com/p0171

This site gives you some common symptoms, causes, and solutions for the error codes from the OBDII scanners. Not sure if it has been posted yet, but everyone checking their codes themselves should check it out.

The home page is:

http://www.obd-codes.com/

but to go to your specific code, just put your code after the "/" like the link at the top of my post.