S4 Strange resonating noise at 1200rpm???

[RyanJonS4]

my s4 makes a strange resonating noise at 1200rpm in any gear. Just want to know if anyone else has the same noise or knows what it could be? Read some where about the same type of noise on a 1.8T, the oil pick up pipe in the sump was clogged with sludge. Any help would be appreciated.
Cheers.

 

[ScottyP45]

could be exhaust heatshields, cat internals loose, cam timing chain tensioner maybe?

mine has a tinny buzzing rasp about 1500 especially when cold, I reckon when I thwarted the sludge problem, the tensioner on the little rear cam timing chain had worn and thats what the noise is.

On a b5 I had, the noise was caused by loose heat shields on the cat and floorpan.