Friday, March 8th, 2013 AT 7:31 AM
Hi. I keep getting codes P0171 and P0174. I have a 99 chevy silverado 5.3L. I already cleaned MAF sensor and replaced air and fuel filter and put new pcv valve and put new plugs and wires on it. I can't hear any vaccum leaks either so I'm puzzled what could cause this. Any help would be great. Thank you.