Yes, back then they were all dependent on the extra oxygen just to keep 'em from clogging.I don't know about now. But back in the early days of catalytic converters if you took what we called the smog pump off it would only be a matter of time before you would be needing a catalytic converter.
does your 2006 race the cold engine a bit at the first morning start up?yes, it's the secondary air injection pump. Pretty sure 2007+ XTs got this. It just blows air into the exhaust to supply extra oxygen which will mix with the leftover raw fuel in the exhaust afterburner-style to heat the catalysts a bit faster during warmup. After warmup, the fan cuts out and the system is dead weight the rest of the trip.