You can locate the oil filter by taking the front right wheel off. Look through the wheel arch and its mounted on the block half way up.
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There is no air filter on this model.
See answer on "How do you change the front brake pads on a 2001 Ford Focus?" for a description of the location of the resivoir. The answer to this exact location is at the bottom of that answer.
Change the fuel filter.
under car by fuel tank......
The cabin air filter is under the plastic cowl aft of the hood below the windshield
Try this hot-link. > http://www.myfordfocus.com/how-to/cabinfilter.htm <
Clogged fuel filter.
The 2001 Ford Focus has 16 valves.
how do i change the alternator in my 2001 ford focus?
The 09 ford focus does not have a fuel filter to be replaced, it has a lifetime fuel filter in the tank. Just found that out myself, after looking for an hour and 2 auto parts store, and a dealership not know where it was, read the owners guide
Where is the coolant temperature sensor on a 2001 ford focus?" Where is the coolant temperature sensor on a 2001 ford focus Where is the coolant temperature sensor on a 2002 ford focus
Probably under vehicle - follow fuel line from tank