55plate ford focus 1.8 tdci, it makes a strange loud vibration noise at 3000rpm.?

Hi, i have a 55plate Ford Focus 1.8 tdci titanium it makes a strange vibration noise (it sounds plasticy, quite loud and it sounds like its coming from behind the dash) it only happen at 3000rpm, it happens in 1st 2nd and 3rd gears,it doesnt do it when im stationery please help as its driving me mad