I can tell you how much fun it is to get a '72 FJ40 to pass every year...
It's not AZ, it's Pima (Tucson) and Maricopa (Phoenix) county having trouble meeting (federal?) air quality standards.
I'm in Maricopa County so I feel your pain. My 79 has passed every year with flying colors, but every year I wonder if this is going to be THE YEAR.
The a**turds failed me on the inspection one year because I knocked one vacuum line off the air canister while doing something. It passed by the numbers. I plugged it back on, had to drive around, get in line and had to go through the entire smog test to get the pass.