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Toyota Corolla LE 1999 high NO failure

I have failed the smog test under the NO( PPM) max is 477 avg 67 and my measure was 730 -What would cause that? I just had my catalytic converter, and purge valve changed ,I had two new 02 sensors put in years ago and i have a new engine but it is burning oil on long distances. What else could be needed to fix to pass smog check?
Answer:

We suggest having a smog check repair certified smog check station conduct a cylinder compression test on your Toyota Corolla. NO stands for Nitrous Oxide. NOx is a chemical created when an engine's combustion chamber temperatures rises above 2500 Fahrenheit. Carbon build-up within your Toyota Corolla's engine combustion chambers will cause increased engine temperature and high NOx. Carbon build-up normally develops in an engine's combustion chambers over an engine's lifetime, and much sooner on vehicles burning excessive oil. The solution to this problem is called an Engine DeCarbonizing. It usually costs around two labor hours at a smog repair station. It will remove a good amount of carbon of your engine's piston heads and valves. This will increase combustion space, lower compression and lower NOx. A compression test will indicate whether this is the fault causing your Toyota Corolla's high NO failure. posted by SmogTips Support

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