Ok, I need to interject here:
I've never been a big fan of "fuel injector cleaner" additives.
I use a fuel stabilizer in off-season on all of my gasoline engines. Lately, I've been focusing on ethanol treatment when storing vehicles.
This along with fuel filter maintenance has kept all of my engines in top shape.
Last year, my son's car was being repossessed so I gave him my newer vehicle and bought his '04 Mustang GT.
It had a cracked intake manifold (plastic) and while replacing it I sent my fuel injectors to Cruzin Performance
for cleaning and flow testing.
The price was right and they came back with new O-Rings, numbered and ready to be re-installed.
You can go on Rich Jensen's website (owner) and view the flow test results when they're done.
Then a couple of months ago, I had a SES light on my '00 GMC Z71 that turned out to be a knock sensor. Replacing the pair of sensors required the intake manifold be removed, so again I sent my fuel injectors to Rich.
This might be overkill, but I know for sure the condition of my injectors rather than adding a bottle of potion to my gas tank and guessing at the outcome.