I have an 05 Canyon with a 3.5 5spd,I'm having abit of trouble with a check engine light and the dealer can't seem to figure it out. I bought the truck about 3 weeks ago as a gm optimum used vehicle with 50,000 Km on it. within the first week i got a P1133 code and took it into the dealer. They Replaced the sensor and reset the code. After about 100-200 km it came back on, Took it back in and they did some kind of update and replaced the sensor again. A few days later after about 100k it came back on again. they replaced the sensor again and thought maybe the new sensor was faulty. So a few days later the code comes back again. this time they just reset it and did an Injector Flush. Sure enough after 100k today......code is back on. made an appointment for monday morning for them to try to figure it out again. Has ANYONE had this problem as well? or have any ides what it may be?