First things first. ALL gasoline fueled vehicles produce CO2 when they are running. Period. Generally, for emissions testing, CO2 content is noted as a %, but, not tested. You probably mean CO, or, carbon monoxide, not carbon dioxide. (CO2) Very different animals.
In order to be helpful, you have to post the actual tested CO content in the exhaust gas to make a meaningful diagnosis. Your failed emissions test results must tell you what that value is. You should also post the maximum allowable CO content in the exhaust gas, usually as a PPM value. (Parts Per Million) It's helpful if you post ALL the test results along with their MAX allowable values. If you don't do that, chances are you are wasting your time in this format.
Chum lee
EDIT: Your test results should look similar to what landyacht318 posted above. I don't know if Utah still does the same but there should be two sets of test results. One at 15 mph (low speed/load) and one at 25 mph. (higher speed/load) California is one of the most restrictive states in the USA. You must pass both low and higher speed tests to pass the test. (at least in California) Utah may vary.
