2000 Mercury Cougar Owner In Search Of Answers

I have a loud humming noise coming from under the hood whenever it's in idle or reverse. Upon acceleration, the noise disappears but then comes back any time I come to a stop. Any ideas?

it depends what u got? a 4cyl,v6 cause the v6's feen out like that.. it could be your feul circulation, feul filter,pump,or injectors get them checked.

its a common problem on v6 cougars, its your iacv valve it is going bad. go onto www.newcougar.org and u will see a temp fix for it or buy a new iacv valve.