The K & N Air Filter alone will not affect your pick up truck from passing
the smog inspection. If the air filter "housing" is changed, that might. But
the air filter itself will not cause a smog inspection failure. Sometimes
vehicle owners change the filter AND the housing; with a housing not
approved for use in California. These air filter housings are usually
missing certain PCV connection points; which the vehicle owners will plug
up. These types of air filter housings built for Chevy trucks are not
California approved or certified and will cause a smog check failure. But if
all you've done is installed a K&N Air Filter in your Chevrolet Silverado's
factory air filter housing your pickup truck will not fail the smog check
because of it.
posted by SmogTips Support
