The Emissions Pass Protection (part #0212) and 3-step kit (part #2630) perform different functions. The 0212 cleans intake valves and fuel injectors or carburetor(s) in order to idealize fuel/air ratios and restore the factory injector spray patterns. In turn, this helps control the products of combustion (as well as improving idle, acceleration, and overall drivability). Additionally, the 0212 contains an additive that helps further reduce emissions. It’s the presence of this additive that necessitates that the emissions test be performed while 0212 is still in the fuel. The 2630 kit will clean more areas of the vehicle than #0212 will, including the throttle body and the combustion chambers. This can lead to a dramatic improvement in emissions and drivability. However, it does not have the emissions-reducing component. If the vehicle truly has problems, though, neither product may help enough. For instance, if you have old spark plugs, a faulty plug wire, or bad oxygen or mass air flow sensors and you apply either product, you’ve still actually done nothing to correct the problem. Instead, you’ve just temporarily covered up some of the symptoms and it’s only a matter of time before the catalytic converter dies. (Remember it’s the catalytic converter that reduces all three types of emissions.) If your vehicle has been on the cusp of failing the state emissions test in the past, then 0212 is probably the better product for you but you need to have the vehicle serviced. However, if you’re only concerned because your vehicle is getting “up there” in age or mileage but all the ignition components and sensors are working properly, then 2630 will give you the most benefit.