I have a 2004 Trailblazer 4.2L I6 and was wondering if anyone had a tuner or know where I can get the truck tuned. I have been having problems with my O2 sensor throwing a code. I have 110000 miles on the truck and recently put a new catalytic converter and o2 sensor in the truck. Everything was fine for about 1000 miles but now I keep throwing the catalytic converter effiecency (sp?) below threshhold. Does anyone know what the problem could be or know where I can get the code blocked or tuned so it doesn't show up anymore without doing PCM for less or something like that. Thanks!