The point you are missing is that a fuel injector has parts that will not be cleaned or helped in any way with fuel injector cleaner. The majority of fuel injector failures that we (the 3rd gen section) have experienced are due to the electrical side of the injector failing. Because there is no service port the fuel rails will need to be split and a fuel service port added in order to use that kit. Along with blocking the fuel return and disabling the fuel pump. It’s not a simple thing to do. If you have done it on a 3rd gen 4Runner then please enlighten us on how easy it is to do and what you did.