My Focus has a 16v Zetech engine and it has trouble idling, a sticky throttle, and very hard brakes at times. I looked at the back of the throttle body to check a few of the vacuum hose connections out and one of the ports is completely missing a hose. I bought the car from a guy who fixed it up after it had a front-end wreck so I'm not really surprised. The port is sucking in air so I assume it is for a vacuum hose of some sort and the engine runs smoother with it covered. The picture below shows the port with the missing hose (it’s covered with a 1/4" hose with a bolt in the end of it to plug it up for now). Please help me identify what this missing hose goes to from there. Also, there are two screw holes in the firewall that look like they should be holding up something possibly. I don't know if that's what the hose should go to or not. I've already checked the hoses leading to the EGR solenoid, the EGR valve, the EGR feedpack sensor, the brake booster, and the vapor canister purge valve. Thanks for all your help!