If the vehicle has failed as a result of high CO and HC, the CO failure should be diagnosed first. Here is some general but hopefully helpful information:
How old is the cat?
I highly suggest Emissions Now right off state street in Murray. Don is an honest mechanic that will always give advice on how how to get passed.
I honestly don't know how old the cat is... I just bought this truck this month... It passed emissions before I bought it. And Murray is a little far for me right now.
Check tune up stuff first. What rpm was you idle test performed at? I dont know how there machines work. Here in Cache Valley the idle test can be performed up to 1200 rpm. So if you can bump the idle to 1100 you might be able to get it to pass by doing that. I do it all the time
Change the oil right before you go. You'd be surprised how much difference it can make. Do the tune stuff as well and the higher rpm will help a lot too.
With as high as both are probably cat converter and/or O2 sensor. Tune up only works for high HC with 100 over and below on these engines it seems. Struggled to get mine to pass for years with doing plugs and tune ups until last year when the HC went into the mid 300 range and finally had to buy a new cat and O2 sensor and the change was drastic.
I have tried and tried and tried and even though I have done a full tuneup it still failed... Any more ideas on how to get me to pass? I'm about ready to give up on it.