It's in the fuel tank.
The 2006 Ford Focus runs on regular unleaded.
1g.
On a 2006 Ford Focus : The fuel pump shut off switch ( inertia switch ) is located in the front passenger's footwell behind the kick panel ( there is an access hole )
Drop the fuel tank.
Change the fuel filter.
According to the 2006 Ford Focus Owner Guide : The fuel tank holds ( 14.0 U.S. gallons )
Probably the fuel filter. Change it.
Drop the gas tank.
Unless you have fuel injection.
With your hands and tools
fuel filter is located under veichle , in front of fuel tank. Right front corner.
In front of gas tank on pass side......