So, i have fault codes PO101, PO172, PO175, and PO455. I replaced the bank 1 sensor 1 O2 sensor about a year ago. I replaced the purge valve solenoid and canister at the same time. Truck ran great until about a month ago right before inspection was due, ofcourse. So, 101 is MAF, i know it's good. 172 and 175 is bank 1 and 2 02 sensors. 455 is large evap leak... WTF. I need help folks....