In the fuel tank.
According to one of Fords websites : For a 2000 Ford Focus : ( Motorcraft FG-986-B fuel filter ) * the website only shows 1 fuel filter , so I assume it is the same for the 2.0 litre SPI engine and the 2.0 litre Zetec-E engine
if you mean the 1.3 endura engine no and if you mean the 1.25 zetec i think it only came with a fuel shut off swich
According to the 2000 Ford Focus Owner Guide : ( 50.0 litres / 13.2 U.S. gallons )
56 liters
35 - 55 psi
Probably the fuel filter. Change it.
4 to 6 pis
Under the car, between the fuel pump and the injector pump.
Do NOT use Diesel fuel in a Ford Focus. The engine will stop running and you will have to drain the gas tank to rid the car of the diesel fuel. Gasoline engines are not designed to run on diesel. They do not have enough compression to cause the diesel fuel to combust The only engine used in a 2000 Ford Focus was the 2.0 which is NOT a diesel engine.
Try either in rear trunk compartment left side or in one of the kick panels
Drop the gas tank.
Fuel filter.