I am new to this board and mostly new to working on Foci (generally accepted form for plural of Focus?) though not entirely new to Foci. My fiancee had an 05 3dr hatch of oddly the same color as mine. Anyway...
I never did any work on her car as it was under warranty when she had it, but I have a fairly extensive history working on compact cars. I was surprised to find that I could not open the airbox on this car and through this site (from Google) found that it is in fact probably a money making scheme disguised as Ford's way of saving you time, trouble and money in the form of a sealed dealer-only replaceable item that should last the lifetime of the car.
Ok, well that doesn't sit well with me. I like tinkering and I have seen the how-to posted for making a stealthy CAI by replacing all the junk under the airbox with a cone filter. I could easily do that as I have a K&N cone filter laying around. What I wonder though, is it possible to just eliminate that whole convoluted mess of the sealed box and just put on a tube with the filter after it? Will I be tripping codes like crazy or will everything function if some things are just left to dangle? I've never run into problems like this on my old cars (3 S Series Saturns and a Neon). Of course maybe they weren't nearly as complicated (technologically advanced?) as this car.
Anyway, thanks for all the other amazing how-tos and general information. I have a feeling I will be visiting this place often!
2007 Dark Toreador Red ZX5 SE "Chamesh" - חמש - means 5 in Hebrew...for 5 doors and the fifth car I've owned. "Ch" like you're hocking something up...ok so thats gross but thats the sound.