So it was ten below and my 2005 focus st has always acted like it had a carburetor and you have to pum the gas or even hold the pedal down to get her to start in the colder weather. This time i must have pumped it once too often and it back fired and the compression blew up the top end of the air intake box. I ordered up a replacement and it runs fine...but now the brakes are suddenly squishy. The timing is very odd as the brakes were fine before. There is a little off shoot tube just below the gauge that tells you your air filter is still good or not...but it didnt have anything attached and all videos ive seen of removing this box never have anything like a brake booster / vacum Line attached there...its just left open. Any thoughts on why i suddenly have squishy brakes after this incident? I did run it in the cold not knowing the box had physically blown out...but it wouldnt maintain idle,,,so i didnt move it.