Vacuum Noise - Ford Forums

datalinksvc · 03-03-2008, 05:14

I have a 2001 Lincoln Navigator with 120000 miles that runs well but has a problem with what sounds like a loud vacuum noise that will sometimes happen after braking to a stop. The sound starts just after letting your foot off the brake but stops immediately as the accelerator is pressed. No CE light or any other symptoms.

RickMN · 03-07-2008, 19:52

Is it coming from the inside of the vehicle? If so, that's a sign of a failing vacuum booster. Your engine creates the most vacuum at idle, so if there's a leak in the booster seal to brake pedal shaft, that's when it would make the most noise. As you accelerate, vacuum drops.

datalinksvc · 03-10-2008, 08:43

I managed to put it in park and get the hood open while it was happening. The sound is comming from the intake. The entire intake vibrates and you hear what appears to be it sucking for air. Is it possible the choke butterfly's are closing by mistake?