Do those gas treatments really improve gas mileage?

no. they make the manufacturers rich though

a 5.7 ltr truck will only get so much mileage whether you do the best you can or leave it alone. I've got an old 4.3 ltr. I leaned the distributor out by sound. My gas mileage is about the same as when the truck was new, 21 on the road and 15 or so in town. I keep good plugs in it, filters always clean, and etc. its got 200000 miles on it. The question should be to the the big oil companies and those people who are working on alternate fuel sources. We need our trucks for our jobs and you're not helping us.

This is a decades-long discussion, and you'll hear from both sides, I'm sure.

What is practically indisputable is that the biggest difference you can make is to improve your driving habits. Search for driving tips for high mileage and you'll get some real advice.

My friend is a truck driver and he says that cruise control saves tons of gas because it takes out a lot of human habits and errors and just keeps you rolling smoothly.

Gas treatments were created to correct clogged injectors/carbs. If your car has carbon buildup on the injectors yes it can help, but if the car has no noticeable running condition its not going to help enough for you to realize it in your MPG calculation. Cars were designed to run on gas, theres no magic potion thats going to make the car get better mileage then when it was new.

I have seen many cars with stuck injectors become cured with fuel treatments, so yes they work if used for what they were made for. They can prevent injector issues by keeping them clean but you will see little gain in performance if the car has no running issue to start with.

Loss fuel mileage at high mileage is due to a ton of factors stacked together.

I have witnessed it will clean a carburator or fuel injectors in the older cars.

The gas treatment will cause the plugs to foul out and need replacing sooner than normal if used more than one time.

Best to not use gas treatment.

Good luck and God bless you.

If you have a well maintained, clean fuel injection system, then no, they don't. If you have some varnish that is affecting your injectors spray pattern, then yes they will improve your gas mileage by helping clear the injectors - clean, properly flowing injectors reduce misfires.

Yes

No, but they let you use less gass for you to save money and if you have a truck (not a Hybird) then it is very good you will save alot of money and you will save money on any car and if you have a small car then you will drive like almost for FREE.

ive found that it doesnt i own a yukon denali with a 6.0 engine and it doesnt help a lick

i have a toll bridge across the salt flats.pay or go around!