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.
The diagnosis was a bad fuel injector, the mechanic recommends to replace all six injectors and the cost is $1300. To replace just one is around $563 due to the labor involved since they have to take all of them out to replace it. Does this sound right?