Toyota Repair: 94 4runner fuel leak, oxygen sensor, orings

Question
My 94 4runner has 114K miles and started to smell like fuel from engine compartment. Is it the injectors and if so, How can I tell if injectors or the Orings are leaking? Car runs good but mileage starts to drop. Oxygen sensor was replaced about a year ago with Toyota sensor. How difficult is it to replace the injectors or the Orings?
Thank for your help.

Answer
Unless you can see a leak at the injectors then it's probably not them, a more common cause for a fuel leak is at the fuel dampener located at the rear of the fuel rail on the right bank of the engine, use a mirror and a light to look at the fuel dampener for a leak located at the right side at the rear near the firewall.If it's leaking replace it.