Q&A

My Nissan Quest used to do 19.1 miles to the gallon and lately its been doing really bad on gas milage, instead of 19.1 its gone down to 13.5 miles to the gallon and gas is burning up very quickly.So my husband thinks it could be because the pcv valve needs to be replaced. He went out and bought the part but he cannot locate where the valve is located to replace it. It is not listed in the owners manual, and he has searched many websites to try and figure this out. So my question is this: Can you tell me exactly where this pcv valve is located in my engine/emissions area? Is this a part that can in fact be replaced by the owner with mechanical experience or is it one of those repairs that can only be done through the dealership?
Thankyou, Crystal Ciuba