Massive vacuum leak

[jay289]

I have a massive vacuum leak in the wife 06 Focus.

When you start it the revs up to 4k and then drops to 1500 and says there for around 5-10 mins.

Then all of a sudden it drops to its normal revs, and the sucking noise stops.

The vacuum leak sounds like a big carby with the filter off, but 10 times louder.

I had a quick look last night and all the hose are connect and the inlet manifold is not cracked.

Has any one had a problem like this, and where was the vacuum leak.

Thanks

[DZFord]

Yeah a friend of mine had similar problems with her 06 Focus (including the rev to 4k) turned out to be a leak from a split PCV hose. Cheap part to purchase, PITA to fix as the intake manifold needs to come off. Local mechanic did the job for her. Not saying that this is necessarily the case with yours, but just something to consider as a source for the leak if there is nothing immediately obvious.