1994 Mustang GT, idoling, problem

It's right by your gas tank. Jack up the rearend of your car, it's right underneath the spare tire. Once you've replaced it, before starting the motor, make sure you turn on the ignition to accessory (the spot right before it actually cranks the engine over) to where you hear the fuel pump turn on. Then turn it back off. Do this like 3 or 4 times before trying to start the engine. This will fill up your fuel line with fuel, because air gets into it when changing the fuel filter and depressurizes the system. Otherwise you'll be cranking the motor over and over, wondering why it's not starting.