05 trailblazer with the v-6 4x4 Engine Light is on and the code that came out of it is P0171 (System too lean. Bank 1) Any ideas with this. Seems to run fine. Just put new tires on it and had oil changed. The tires are the same size as factory tires so no chang in tire size.

 

this might help http://en.allexperts.com/q/Chevrolet...de-P0171-1.htm

or you might try cleaning it first: http://www.spydermagazine.com/2002/M.../maf_clean.htm

here is some theory behind MAF sensors: http://www.knfilters.com/MAF/1MAFSensorVideo.htm