I have a 2009 Fiesta, 24,000km's, recently the front left tyre has been making a weird noise, like the tyre is flat but it is not, someone described it as a thrrr, thrrr, thrrr sound. Ford said that i had damaged the rim, they said that they fixed it but the problem persissted. I bought a new rim and tyre and the noise is still there. It does it when im just coasting, the steering is not affected at all, and turning doesn't affect it either. someone suggested bearings, but they thought it would be worse when i turned. please help!! Thanks!!

I have a 2011 with the same noise.Drove me nuts trying to locate it. I have been a mechanic for 15+ years and I have determined the wind in the wheel well causes the cheap plastic used as the inner fender well is rattleing and since its such a small car a small sound will travel. Sound is more intense in the cold weather.
To test, sit in your car with windows up and have someone gently tap on the wheel well and you may find that is the sound your hearing. They did not secure that part to its fullest I think. If thats is all it is, all you can do is add some dampening points where it is loose. Hope this helps.