I don't understand how a 2005 ford focus never needs the air filter changed. It has to get clogged eventually.

Could be a locked up oil pump if you're fortunate. It sounds though like you've broken or seized a bearing or several.
Have a really good,honest mechanic take a look.
don-ohio

your cabin air filter is probably clogged up, that can cause the ac to actually freeze up and wont feel cold until the car stops and thaws out. replace your cabin filter and see if it doesnt help. ehow.com has a good step by step for the process.

it depends on what oil filter you have fitted on your car if you have the screw on type it woud be at the back of the engine on the offside.and the other filter sounds like its the pollen filter. hope this helps

change the idle sensor

i think it is 105,000 miles. They go much longer. It is a free wheeling engine in the U S. No damage will occur.

2005 Ford Focus L4-2.0L VIN N Hello your vehicle has a timing chain, you do not have to replace it ever... It was designed to last the life of the vehicle, unless you have a water pump, or a timing pulley or even a timing tensioner go bad, that is when you would service the timing chain. I added what your vehicle needs at it's 90,000mile service below, hope this helps... (subytech1)

Inspect Ball Joint
Brakes and Traction Control
Inspect brake pads, shoes, rotors, drums, brake lines & hoses, and parking brake system. Cooling System
Inspect cooling system and hoses. Exhaust System
Fluid - A/T (Except 4F50N & 4F27E)
Inspect automatic transmission fluid level on all other vehicles, if equipped with dipstick. Heat Shield, Exhaust
Steering and Suspension
Inspect steering linkage and suspension. Vehicle (Multi-Point Inspection)
Perform Multi-Point Inspection (Recommended by Ford) Refer to Routine Service. Wheel Bearing
Inspect wheel ends for endplay and noise. Replace Cabin Air Filter
Replace cabin air filter, if equipped. Engine Oil
Fluid - A/T (4F50N & 4F27E Only)
Change automatic transmission/transaxle fluid on all vehicles equipped with 4F50N & 4F27E. Inspect automatic transmission fluid level on all other vehicles, if equipped with dipstick. Fuel Filter
Oil Filter, Engine
Rotate Tires

is your focus a diesel ?? i would replace every 12,000 miles or check once or twice a year you can never change it enough same as oil and filter changes and fuel filter

if it is a flex fuel vehicle, it most likely is the flex fuel sensor and/ or connector- it's located on the driver's framerail just behind the door.hope this helps and good luck

no they are a bit of a struggle and need a bit of patience just remove vac pipes hoses and all screws and they come off eventually !  at one time ford used to make cars for the diy mechanic those days have gone!

do not understand you what you mean. assuming your car was ok before you changed f/filter you need to bleed the fuel system of air. esiest to do would be to loosen fuel line at the injectors and have assistant crank the engine while you observe for clear fuel leak without any air bubbles from fuel line.tighten fuel lines and start engine. might have to repeat a few times. good luck.