Fuel Injector Cleaners

In the following scenario, What would produce the best results:adding the cleaner before a long trip,or driving around town, till you need a fillup again?Using Chevron FIC with Techron, in a 2004 Toyota Highlander with 50000 miles.

If the vehicle is running fine with no noticeable problems then why even worry about injector cleaner.
If an injector even starts to become a subtle problem you will notice it at an idle. The idle may be faintly rough or the engine will stumble now and then; assuming plugs, wires, etc. are good.

The cleaner certainly will not hurt anything, but if the engine is idling smooth then the cleaner is not really needed.
The problem of “dirty injectors” is vastly overblown IMHO.
If a cleaner is going to be used in this situation my preference is to use it with a very low fuel level so the concentration will be stronger. This will not hurt anything and either method you have mentioned will work fine. My personal preference is open road at speed.

Doesn’t matter. Just put it in the tank and forget about it. You can add it to a partial tank to increase the concentration, but I wouldn’t do that unless you have some sort of problem.

Since there is not likely any problem with the fuel injectors you can do it either way and get identical results – no effect. But if it still makes you feel better to give medicine to a healthy car, do it before a long trip. You use it up more quickly.

Mechanic in a can, fuel injector cleaners that go in the tank, all that infomercial crap…all of it dose nothing, it’s all a scam. You might as well just through your money down the toilet.
The only injector cleaner that dose anything is the pressurized cans that require a regulator, pinching off the supply and return and pulling the fuse for the fuel pump. This should only be done by an experienced tech. And what it really dose is clean the carbon off the valves and heads. Injectors rarely fail in any way. The only injectors that I have seen fail was back in the 80s on GM and Nissan P/U throttle body systems. And they would fail to the point that you would need a wrecker. Sea Fome used thru an intake port ONLY (not in the tank or oil) dose help clean carbon from the combustion chamber. Lastly I recommend to put isopropyl dry gas in the tank monthly.