This thread is great... I am wondering if all this info relates to my car (wife's, actually).
We have a 2005 Ford Focus ZXW (wagon). It has a 2.0l engine with 58,000 miles on it. It has developed what I consider to be a rough idle, seems like it has gotten worse over the last 6 months or so. It runs fine, no stalling or stumbling, just a rough idle.
I went to check the air filter... surprise! It is permanently mounted in the bumper I guess? Who (and why?) thought of that design? The air filter air flow indicator (the clear plastic thing with the yellow indicator that moves the more the air flow is restricted) is barely visible, meaning I assume the air flow and air filter are fine.
I have removed and checked (then put back) what I believe to be the MAF sensor, and it looks totally clean.
The collapsed PCV tube that is being talked about here, do I have the same design or has it been changed? For the life of me I cannot find it, the pictures posted are great but maybe they don't relate to my engine? Looking from above my engine, should I be able to see it, or do I have to go under the car and look up?