Duke,

If you happen to have a friend in the smog business, ask if you can curl up with some of his books that come with his machine or any of the course books he may have that helped him get his license. These books are loaded with theory, explanations and graphs showing relationships beween the 5 gas readings and temperature. Used to be CO and HC were enough. Now you have to look at CO, HC, O2, CO2, and NOX to diagnose cars.

Peter

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Auto Zentral Ltd.