Hi! I got this offer from a mechanic that I had do some work for a recall issue. Was wondering if the 20 bucks would be worth it? Will it actually improve the fuel efficiency? My car, an '06 Pontiac Vibe, has 60,000 miles on it.
Battle rising gas prices with our
GM VEHICLE CARE
Fuel System Treatment Plus
$19.95!
plus tax
Cleans Deposits From:
Fuel Injectors, Carburetors
Intake Ports, Intake Valves
& Combustion Chambers
You can probably get the same effect by putting Chevron Techron or Gumout Regane in your tank, for about $5-7. You are paying him substantially to put their additive in your tank.
I would recommend a DIY treatment once a year or so, and even then, some say that may not be necessary due to federal requirements for detergents in gasoline.
$20 is cheap (for something done by a shop), which makes me wonder if he just adds a cleaner to the gas tank.
Unless you’re having issues, you’ll do well just to skip it, or buy a bottle of Techron at Walmart and do it yourself.
Most people don't need any additives. They are already in all gasolines sold in North America. In normal conditions there is little or nothing to gain by adding more. In this case [b] I would say there could be a benefit, . . . to the shop, but not to you [/b]Is it worth it? Absolutely not. Your Vibe’s fuel system is already spotlessly clean, thanks to all the detergent that is part of all gasoline brands. Don’t even bother with your own additive. You will see no improvement in your car’s performance or fuel economy.
Unless you’ve seen a reduction in fuel efficiency caused by a dirty injector the only thing it’s likely to do is lighten your wallet by $20. I agree that it wouldn’t be any better than a fuel system cleaner you could pick up at Walmart for $5-$8. One product I’ve heard really good things about for cleaning the fuel system and engine deposits is Sea Foam.
If a “dirty fuel injector” problem really exists then this is generally noticeable while the engine is at idle. There may be a slight stumble or roughness/vibration while idling that will disappear when the engine is revved a bit. (This is assuming there are zero faults with engine compression or ignition components.)
Often with mileage deposits will build up on the back of intake valves and this can cause a peformance degrade that will not even be noticeable to you nor will it set any codes.
If mixed strong enough a cleaner can remove those deposits but a better option in my opinion is to feed a raw cleaner through an intake manifold vacuum port. SeaFoam is the product that I prefer for something like this and if you go this route do not be alarmed by the smoke that will start shortly after using the product. This is entirely normal and will clear out soon.
Thanks for all of the responses, guys! It seemed a little silly to me, but at 20 bucks with the implication of better mileage, I thought it might be worth it. Glad I asked! Thanks for saving me 20 bucks! I’ll put it toward my 60,000 mile service that I’ve been putting off 
A bottle of Chevron Techron once a year does it for me.
And I have experienced it smoothing out the idle on a fuel injected engine in just a few miles.
Varnish, gum, mineral residue and plastic fuel tank coatings can somehow pass through fuel filters and cause performance problems. Techron added once or twice a year seem to ward off the evil spirits and it is quite cheap. In fact Techron is sold at a much cheaper price under the Pro-Gard label in my area.