Not sure when they started sec. air inj, but I know they were power robbing emission devices. An actuator for each exhaust manifold would open and an electric blower pump forced fresh air into the exhaust making it cleaner out of the tailpipe.....but if they're grabbing air that was in our atmosphere already what's the point? LOL!!!

It doesn't matter what control unit you have, they all fail sometimes, just do the test like I explained. If the blend door actuator is ok and holds vacumn...its either one of the small plastic hoses or the control head. I've never seen an actuator or line go bad, just the control head....