Bought the wife a focus Since then I've had to replace a few bits and pieces, including the cat and more recently the idle speed control valve.

However, it was replaced with a mondeo one (looking on ebay, it looks like they're the same fitment)

I have air resonating in the air filter, I've taken off the pipe work to just leave the throttle body exposed, started the car and it's still doing it. I can hear air coming from the throttle body.

The only thing i can think of is the idle control valve is the wrong one, but does anyone have any ideas?

2.0 Zetec 2001 by the way.

 

somebody? please! Lol

It sounds as though there is air coming out of the butterfly on the throttle, hence the resonating in the air box. Can't be normal?

 

Had a 1.6 focus do this. Chylinder head sensor sorted it.

 

Sorted mate, stuck another inlet manifold on it and that fix it. New manifold had ISCV and throttle body on it so who knows.

Also, i had to buy 2 inlet bolts as the old manifold had these blanked off?! Who knows, nut it's fixed, cheers mate.

 

sounded to me that something on your intake wasnt sealed properly or there was a crack in the inlet somewhere... but all sorted so well done