Replacing the Dorman air intake hose solved my problem with a cracked 10 year old original hose in a Mazda MPV van. Cracks in the original hose caused the car to fail the CA emissions test and the shop charged $$$ to replace it. I bought it online and installed it myself. It was a simple setup, it fitted perfectly and solved the emission problem. In my experience, Dorman makes pretty good aftermarket parts.