Join Date: Feb 2009
Location: Northeastern BC
I'm not an auto mechanic, just going by what I remember of combustion instrumentation, but here's my guess ...
Based on your 2008 test vs. the current one, for some reason it looks like your combustion looks too rich. Do the tests in Ontario show NOx? If it went down, then somehow things got rich.
As to why, I'd guess it could be a number of things. Blocked or missing air pipe to the cats, O2 sensor problem, dirty or restricted air filter?
You don't mention the check engine light being on, so I assume it's not. Have you had a chance to plug an OBD scanner in? Does it show any stored error codes?
One other possibility is that the test equipment used by the shop is not correctly calibrated or they screwed up the test somehow? Not sure how likely that would be? I don't know how much they usually charge for those tests, but it may be worth getting a second opinion before blowing all kinds of money fixing something that may not actually be broken.
If Princess Auto were a real girl, I'd ask her to marry me.