windstar intake knock

i have a 2001 windstar with 88thousand miles i noticed that there is a knock at an idle around the intake and when you give it the gas with the hood up i hear a vac leak at the back where i can not see ? when you drive it sitting at a stop light it hesatates acts like it wants to die ????? any help thanks grabber-74

Hi
I would bet your the inner baffle in your upper intake is loose and rattling. On the '00's and newer with the different body design they re-engineered the intake. Try your same process (revving with the hood up) while applying pressure down onto your intake manifold. You could even use a 2 X 4 or similar under the rear cowl as moderate leverage down onto the intake. If that stops the sound, you can remove the upper intake and use RTV to re-secure the upper baffle. If you look at the first post in the forum, the sticky regarding codes 171/174 you will see that many have had to RTV the inner baffle after the isolator bolt fix. I have done it twice using Permatex black RTV. If you get it apart, it will be intuitive as to where to put the RTV so that it will secure the baffle.
As to your Vac leak, all the vacuum lines attach on the back of the intake plenum. If you pull the cowl you will have easy access to them all.

Good Luck

I had to replace mine on my 2001.. 150.00 I think.. While engine running I could grab the the upper shell and put pressure on it. It stopped.. I have heard you can pop the baffle out which yes that is true. They say you can run without it. I already replace mine before trying this. The new one is plastic welded to the top of shell they old one snapped on... So if you want to try taking baffle out and see how it runs..