To pass an emissions test (aka smog check), make sure your oxygen sensor is in proper working order. It tests the amount of oxygen in the air-fuel mixture that goes into the pistons to drive them. If it fails, then the car can put too much fuel or two much oxygen in the mix, which, either way, leaves either too much unburnt fuel in the air or does not burn enough fuel to run correctly. Symptoms of this include rough idling, stalling, and/or hesitation to accelerate.

Each and every year, all four of my family's vehicles do, thanks.

When you take care of things, this is what happens.

Sure, just blow into the tube.

Yes I did, thank you...

great idea