[lanceinsb]

I have a 2013 ZL1 / manual with 12,000 miles. Bought it with 5000 miles from a Chevy dealer out of state who told me it was dead stock. About every 600 miles or less I get an engine code for the O2 sensor saying the car is running rich. To date, the local dealer has replaced the injectors, all O2 sensors, MAF - and it still throws the code. This visit the dealer discovered the resonators had been removed, but camouflaged to look like they are there. I am being told that the car will continue to throw the code until the resonators are replaced - at my cost, of course ( I will take this up with the dealer who sold me the car). My questions are: 1) would the resonators being gone cause the car to run rich enough to continually throw a code, and 2) If I do replace the resonators, and the car continues to throw the code, does anyone have an idea of what this could be? 3) Anybody else had a similar problem, and how was it resolved with GM?

Sorry for the long post, but at this point I think they are lost and just throwing parts at it.