ok, so at 2500 rpm everything seems fine, the hydrocarbons and CO% is under the legal limit. At idle the hydrocarbons are about twice the legal limit and the CO% is 1.53 and the legal limit is 1.00. We replaced the sparkplugs and wires, the distributor cap and rotor, thermostat, 02 sensor and we replaced the catalytic converter last year. everything under the hood is stock. we had the same problem last year after we bought the car and the shop we took it to "passed" it but we have doubts.
We took the car into the smog pro guys and they dont know whats wrong...and the renewal is due in about six days...anyone have an idea?

 

Not that I would know, but you need to give the people here a little more info. What year, motor, carb or FI, etc. ?