I have 2004 GMC ENVOY XL the engine light stay on. i do a diagnostic on it the code i get is P1133 HO25/025 INSUFFICIENT SWITCHING SENSOR 1 OR BANK 1 SENSOR 1. also code PO133 02 CIRCUIT SLOW RESPONSE(BANK 1 SENSOR 1) IF ANY ONE CAN HELP ME PLEASE? THANK.

P1133 is a slow 02 sensor or a shorted to ground at the PCM to 02 sensor signal. If the 02 sensor does not cycle fast enought it is called a lazy 02 sensor, the only way to test for this is with a digital volt meter or a scanner. if it will not pulse fast enough it will throw the code so Replace the 02 senor on the driver side bank. Bank one. then clear the codes. The code is thrown do to seveal reasons the 02 sensor could be dirty or it just could be worn out, you could pull it and clean it and try it again or just replace it and be done with it. The cost of a heated 02 sensor is $50.00 at a auto parts store or the dealer might charge a little higher but the cost in savings of fuel is well worth it.