They are just missing the problem ,haven't really looked or don't know what they are doing. My poor Dad wasted $700 taking his 1985 Crown Victoria to dealers for a vacuum leak they couldn't find. A retired Plant Maint. Mech found a faulty two inch vacuum hose within an hour. I haul Intermodal containers full of parts made and shipped from Mexico, China , Korea. They all are assembled into your proudly made in the USA vehicles, including Ford