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.
Try a good Fuel Injector Cleaner first. It be a lot cheaper than a new injector. Do not skimp on this, buy, a good cleaner. The Seafoam be good, also, I have used Lucus Fuel Injector cleaner with good results. I think that the name. Autozone has 2 different brand of injectors @ $76 and $172 without tax. 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.