Ford focus issues

[derf]

My wifes car has been running like shit for a few months, not a persistant problem, but every once in a while it gets a nasty stumble and looses power for a second. I couldn't figure it out and I brought it to a shop a while ago and they said there was nothing wrong with it. Anyway, last night she went to a friends house and on the way home the car would die as soon as she would hit the brakes.

So I went out to look at it this morning and it worked fine until I came to a stop light then it started to sputter and tried to die again. I was able to quickly find a leaking vaccum line by the sucking sound I heard. There was a small but visible hole in ths line so I took the problem line off the spare focus in my yard, and replaced it. Car ran fine for a few miles then all of a sudden it started to stumble again. same thing vaccum line leak, I can hear it, not as loud as the last one but still there.

So then i spray all the lines down with starter fluid, and nothing no surge like it would if it was sucking air, but a second after I pull the spray away it surges like I just gave it some starter fluid. My guess is that it took a second to work its way through the system.

Anyway, now I'm stuck with a diagnosed problem and can't find the damn problem area.

Btw, car is an '00 with 125k miles, and I am the only owner.

And as an added bonus I replaced the front brakes for the 9th time last thursday.