Slight noise when driving around 60-70 mph

[Tommyjohn]

I have a slight winning noise when I drive In between 60-70 mph. It comes and goes in response with the throttle only at this speed. My Expedition is a 2004, bought in 2010 with 24,000 miles. I have 50,000 miles now. I also tow a camper that weights about 4,000 lbs loaded. The only problem I have had so far is my air blend motor is going bad, I get the thumping noise with my rear air. I have only changed my differentials to Royal Purple, trans fluid changed to Ford spec full synthetic oil and engine oil is full synthetic. I also installed a K&N air filter.
Thanks for your help

 

[Tommyjohn]

I forgot to mention that I had all spark plugs replaced and 1 coil replaced also.

 

[ericnyce]

Sounds like your about to chase the noise like many have on here. See you have viewed my post so you know what not to do haha. Good luck and let us know if you have any luck

 

[FordandPolaris]

Does it sound like it comes from a certain area of the truck? My old man's 04 had a whining come from the back left and it was his wheel hub having gone bad, but that was also with almost 100,000 miles more on the truck than yours. Things to check are if the tires look oddly worn in front. Lots of times this can cause humming or whirring after a while (wouldn't hurt to rotate them if you haven't lately or since you bought the truck). Can you hear it better or worse with the windows down? The more detail, the better we can help you out!