narge79

I am perhaps missing something, but it sounds like there are two distinct problems. One is the "low" hum only heard at some degree of speed and seems to be resolved by changing bearings. Two a "high" pitched noise that can be heard at idle and at speed and may or may not be intermittent. Most people, myself included since I do have the high pitched noise, suspect that this is a fuel pump problem although information from this forum suggests that replacing the fuel pump does not solve the problem. Note in my case for the most part the noise goes away when the vehicle gets warmed up so by the time i get to the dealers it is gone.

The "high" pitched whine in my MKX doesn't seem as noticable now, after a 18 months. Either its quieter or I have grown used to it. The noise is/was most noticable when idling, since there's no road noise to cover it. A Ford master mechanic friend advised me relatively quickly that its the fuel pump and there's no guarantee that a replacement wouldn't do the same thing. Since it is no long as noticable to me, I've let it go.

I'll be interested in whether the replacement fixes the high-pitch whine. I have a new MKX with the same type of noise that is already driving me nuts. Please post the results of the replacement.