I worked for a GM dealer for years, I personally dont think you need O2 sensors. I think, and it sounds like you have a vacuum leak. Which 90% of the time it is an upper intake gasket. You will need a code scanner to read the fuel trim under a load to verify. When the fuel trim reads -10 or more that will tell you that you have a vacuum leak.
Wednesday, March 26th, 2008 AT 9:51 AM