Engine light came on while driving around the other day, did nothing unusual and was just driving it lightly. The code that was pulled was po171, description was "system too lean bank 2". The code was cleared and it has not came on again yet. In your opinions what should I do?

Mike will prolly know the answer, could be an o2 sensor, but i dunno much about the 8s computer system.

Ok thanks, I actually just found a mouse nest inside my air box. It made a hole in the air filter and put it's nest in there. How the hell it got in there god only knows but I got it out and am getting a new filter tomorrow. I'll see if that does the trick.

yeah if you clear it and it doesn't come back, you're done! it could totally be related to the critters in the air filter

Bank 2 always refers to the o2 sensor located in your catalytic converter. I dont think the mouse nest would cause this specific code; if anything it would screw with the maf. you might want to check to see if the cat is failing. or the sensor itself could be going.

the code has to do with what the o2 sensor is telling the computer, but rarely have i seen it actually being the o2 sensor. other causes are the maf sensor reading incorrectly, a vacuum leak somewhere, or even dirty injectors/spark plugs. i usually pnly see o2's go bad on much older cars. if i could hook up a scanner and watch the datastream i could help eliminate the possibilities but its a little more difficult diagnose via the web.