Are Arizona emissions tests bogus?, test history makes me wonder... Options

[914GT]

I was bored with work and I was curious how the emissions test results compared going back over the years on one of my cars. I kept almost all the inspection results for an Acura Legend that I bought new in 1987. My daughter has been drivng this car the past few years, and I still maintain it. I picked this car as I know its history and I always maintained it well. Basically the 2.5L engine has had little done to it over the years, plug changes a couple times. Replaced and/or cleaned the injectors a couple of times. The usual routine filters, etc. It's never failed emissions. I replaced an O2 sensor once because the engine service light came on.

I don't see any rhyme or reason to the numbers. We'll see how it does next month when it's due. There are some screwy variations over the years that I can't correlate to any particular repair or maintenance item. Makes me suspicious of the whole thing. I'd expect some variation due to the car and testers (all at the same location) but there are some years that are drastically different.

[Allan]

Got some major swings showing. Especially in '92 and '95. Could it be fuel related? Same brand, grade location, etc?