What is code p1133 for the chevy silverado?

The Chevy Silverado fault code P1133 stands for Heated Oxygen Sensor (HO2S) insufficient switching (bank 1 sensor 1). This means the engine computer has detected an issue with an oxygen sensor which is causing it to enrich or lean down the fuel supply. A bad sensor will reduce the fuel economy, foul smelling exhaust fumes, a rough running engine and will likely fail emissions tests. The bank 1 sensor 1 oxygen sensor Is located on the right side of the engine near the firewall, in the exhaust between the engine and the catalytic converter. You need a 22 millimeter deep well socket and ratchet to remove it. Carefully disconnect the electrical connector on top and place the socket over it and rotate counterclockwise to remove it. When installing the new sensor hand tightened to make sure You don't cross thread it, then tighten it with the socket another half to 3/4 turn