If the injectors are leaking, you replace them. They are not repairable. If the o-rings are leaking where the injector mounts into the fuel rail, the o-rings are replaceable. The plenum has to come off, then its not to difficult to carefully pry the injector rail out and replace injectors or o-rings, after disconnecting the bolts and fuel line. Dont recommend messing with it if you are unsure. Putting it back together wrong and running it could cause running problems, or worse, a fire.