I’ll agree with @db4690 that an injector service is far more than adding a can of Techron to the tank. I think it’s also fair to point out that all these “wallet flushing” services were originally designed out of legitimate mechanical needs and benefits.
20 years ago I refused to buy into the need for a MotorVac or any other fuel injection service. Then I took a job where I did them. I saw plugged fuel injectors brought back to life, rather than having to remove the fuel rail and replace them. I saw hydrocarbon emissions cut in half with nothing other than a fuel injection service. I saw long crank times fixed, hesitations gone. I saw physical evidence of the system cleaning the valves, pistons and combustion chambers.
Power steering system flushes were also needed more in years gone by. It seems like many Fords turned the steering fluid black by 60,000 miles. Lots of GM cars had “morning sickness”, where the rack and pinion was deteriorating and causing poor power steering when cold. Flushing the fluid might not have fixed things, but improved it enough to put off that $700 rack replacement for a year or so. Not a bad way to spend $59.95
Of course fuel quality has improved over 20 years, and so has fuel system and engine design. Cars just don’t need this service as much as they used to. It’s still a beneficial thing to those that need it. It’s a problem when it’s recommended through odometer surfing rather than actual diagnosis.
My vote is with db4690 and asemaster in regards to flushing.
The incident that circuitsmith mentioned is something that reflects badly upon the mechanic profession. Power flushing a manual transmission is bunk.
While I’m not defending for one minute the practice of what that Toyota dealer is doing, it could be that the service writer is under some pressure (threat of unemployment) to sell garbage like that. Going on up the scale, it could also be that the service manager is under the same threat from the owner.
Yeah I agree with db4690 and asemaster. The Buick dealer used the can hooked directly to the fuel rail for me. I was having an intermittant extended crank. Sat in the shop trying to duplicate it with a fuel pressure guage, then all of a sudden the pressure dropped to zero indicating an open injector. Hooked the can up to clean the injectors and that solved it. So it worked but there was a problem, and it was the professional treatment.
When I was working at the dealer, there was a point in time when we were “encouraged” to upsell injector flushes, power steering flushes, evaporator housing cleanings, and even some more questionable things.
When the service manager realized this was “much ado about nothing” . . . not to mention that some of the machines took some time to set up, that was the end of it. I’m happy to say I successfully resisted upselling this stuff.