Hi I have a problem with my 02 Ford Focus 1.8 Diesel. Basically when the rev's go above 2000 there is a wooshing noise as if air is escaping somewhere, I've looked whilst stationary and the noise isn't there so it only appears to be whilst moving. I've looked at another post http://www.fordownersclub.com/forums/topic/15515-focus-18tdci-wooshing-noise-when-accelerating/ which suggests its a split in a pipe, i've looked at the same place as the picture on that post but it must be a different model however I did find another pipe that looks like its corroded (see attached pictures)
Any ideas what it maybe? and how much it may cost to be repaired?