my ride was making a small chattering noise.Recently i did a tune up so when i was purchasing the parts i made sure i got the most overlooked thing ,the pvc valve.i changed everything on the car and i changed the valve and it turns out the old valve was burnt up and it wasn't working properly.so i guess that the manual really knows what its talking about when they recommend it to be changed every 30,000 miles.just wanted to share that with you'z . peace out