Most DEQ testing facilities check to see if your "service engine soon" or "check engine" light are on. If it's on, you automatically fail, if it's off, they most likely won't check any further. 1996 is the first year of OBD 2 diagnostics on board automobiles. OBD 2 systems self monitor emissions, so usually monitoring tail pipe emissions won't be needed. I own an automotive repair shop in Oregon, so perhaps Washington is slightly different.