[JohnC]

Originally Posted by Boog

Been through the same issue with my 97 Burb. The cat efficiency is just below the optimum so it sets the light. The truck still runs fine. I wasnt' ready to spend big bucks for a new cat so I used another trick to stop that annoyance. You use one of the deep spark plug non foulers in between the rear O2 sensor and the pipe. You have to drill the hole in the non fouler just a big larger to clear the sensor tip then just screw them in. What it does is it moves the O2 sensor an inch or so out of the exhaust flow. Think of it as a spacer. The non fouler screws into the exhaust pipe then the sensor screws into the non fouler. Stock appearing and I've been running this on mine for 5 years now and no more codes.

That's a great tip!!!