The definition of a rule is  an official regulation, code of regulations or set practice. An example of a rule is that a red light means stop. An example of a rule is an employer demanding their employees arrive at 8am.
New injectors cost anywhere from $80-$120 apiece, making their replacement a somewhat pricey endeavor. There are three types of injector leaks-it can leak fuel into the manifold from the nozzle, it can leak fuel into the engine compartment from the fuel rail, and it can leak air (vacuum leak) from the manifold.
Most good repair shops will have an injector cleaner that they can pump right in to the injectors. It's a heavy solvent that dissolves deposits, debris, gelled fuels, and anything else that gets past the filters. This process takes around 3 hours to complete and can run around 200 to 300 for Labor and the solvent. replacement fuel injector is about $78 - $91 each + shipping. Follow the link below. You need to install it yourself or find someone to install it for you.