little breather that presses into the main breather at the front of the engine
its like a little insert that poke out teh top then has a breather tube coming off it and going up

i had similar probs, changed everything then tryed that and done £18 from ford

mine rattles, could remove it and see if yours does, new 1 didnt
i have since stripped the car i could send you mine for a tenspot 1st rec

just went out to take a picture
its pulled on in the last pic
also have maf etc