Carbon Monoxide or CO is formed by combustion in an over rich mixture. The idle screws will only lean the mixture at idle. If your engine failed at part throttle, it cannot be fixed with the idle screws. It may be due to some problem in your carb or intake. Do you have a clean air filter?
Is your carb float setting or your fuel pressure right?
What color are the plugs? Do they show a rich mixture?
How is your Hydrocarbon reading? Rich mixtures should also produce high Hydrocarbons.
The emission inspection was done at idle. The hydrocarbon portion of the test passed very well. The air filter was recently replaced and I have not check the plugs as of yet. Maybe some carb cleaner and lean out the carb a bit????
Was there anything they tried to get you within limits? They should have tried some minor adjustments eg. adjust carb/timing before failing you. Do a search on this site for sea foam, the stuff works awesome.
Thanks for all the information guys! I have been busy and have not had time to work on the truck. Hopefully, this week I will try some things and if I have time I will run it through. I will report my findings.