Best Additive For Gas Mileage: Compare 10 Fuel Treatments

#1 · Best Overall

1. Hot Shot's Secret Gasoline Extreme

• Weight: 2 lb
• Size: 32 Fl Oz (Pack of 1)

Best for: Economy-focused fuel-system cleaning.

Why it ranks #1: Its listed features explicitly claim fuel-economy improvement up to 7.9%, and the 32-ounce formula is designed to clean and lubricate gasoline fuel-system components.

Hot Shot’s Secret lists a fuel-economy improvement claim of up to 7.9%, making that the most specific mileage-oriented feature here. Gasoline Extreme also claims to clean, lubricate, and safeguard components ranging from valves and injectors to rings and upper cylinders, linking its economy focus with broad system care.

The 32-ounce liquid targets multiple gasoline-engine parts, including pumps, injectors, valves, rings, pistons, and upper cylinders. Hot Shot’s Secret connects thorough fuel-system cleaning with combustion efficiency, engine power, and its stated MPG claim of up to 7.9%. That broad component list can appeal to a driver addressing more than injector deposits, while the larger bottle supports a supply beyond a single small-dose application. The supplied facts do not specify a treatment rate or interval.

Skip it if you need a stated amount per tank; K&N Performance+ Octane Booster gives a treatment capacity of up to 18 gallons.

This suits gasoline-engine owners prioritizing broad component cleaning and a product with a stated, though maximum, MPG claim. The listing omits dosage and interval details, so buyers should account for that when planning routine treatment.

Listed on Amazon as: Hot Shot's Secret Gasoline Extreme Fuel Additive, 32 oz

#2 · Largest Bottle

2. Lucas Oil Fuel Treatment

• Size: 128 Fluid oz

Best for: Bulk gasoline-and-diesel treatment.

Why it ranks #2: The gallon bottle provides 128 fluid ounces, and its features specifically say it increases MPG while cleaning and lubricating the fuel system.

The one-gallon bottle sets Lucas Oil Fuel Treatment apart for drivers who want a larger supply of a formula listed for both gasoline and diesel. Its stated functions include cleaning and lubricating injectors, carburetors, and combustion chambers, pairing fuel-system care with claimed fuel-economy and power benefits.

Lucas Oil describes this treatment as serving gasoline and diesel fuel, making it relevant to households or operators maintaining both fuel types. The listed cleaning and lubrication reach injectors, carburetors, and combustion chambers, while the product also claims to neutralize sulfur and other contaminants. At 128 fluid ounces, the bottle offers a bulk supply, but the supplied details do not state a dosing rate, so buyers cannot calculate its number of treatments from this listing alone.

Skip it if you want a small, specified single-treatment dose; Red Line SI-1 lists one 15-ounce treatment and a concentrated formula.

This suits drivers maintaining gasoline or diesel equipment who want a large bottle for ongoing fuel-system care. Because the supplied listing omits the dose, it is a weaker fit when precise per-tank measurement or treatment planning is essential.

Listed on Amazon as: Lucas Oil 10013 Fuel Treatment – 1 Gallon

#3 · Best High-Mileage Fit

3. Valvoline MaxLife Cleaner

• Size: 12 fl oz

Best for: High-mileage deposit removal.

Why it ranks #3: Designed for engines over 75,000 miles, this 12-ounce cleaner is described as improving fuel efficiency while removing deposits from high-mileage vehicles.

Valvoline MaxLife specifically targets engines over 75,000 miles, centering its use on removing stubborn deposits in high-mileage vehicles. The 12-ounce complete fuel-system cleaner is also described as restoring lost engine performance and improving fuel efficiency and power, making it a mileage-conscious maintenance option for older cars.

The high-mileage focus gives owners a clear threshold for considering this treatment: the product is specified for engines above 75,000 miles. Valvoline links stubborn-deposit removal with restoring performance, while its injector-cleaner description connects fuel-system care with efficiency and power. The 12-ounce bottle is listed for cars and includes a bottle component, keeping the product category and intended vehicle type clear. The supplied details do not specify a treatment dose or a numerical MPG change.

Skip it if you want stated corrosion protection alongside deposit cleaning; Chevron Techron High Mileage lists multiple corrosion inhibitors for metal components.

This is for car owners with engines beyond 75,000 miles who want deposit removal and fuel-system cleaning tied to performance and efficiency goals. Its listing gives no dose or numerical MPG result, so those seeking quantified guidance should compare specifications.

Listed on Amazon as: Valvoline MaxLife Complete Fuel System Cleaner, 12 oz

#4 · High-Mileage Protection

4. Chevron Techron High Mileage Cleaner

• Weight: 12 oz
• Dimensions: 3.16 x 2.66 x 8.9 in

Best for: Classic-car deposit care.

Why it ranks #4: This 12-ounce cleaner targets vehicles over 75,000 miles and says deposit removal can help protect engine efficiency and fuel economy.

Compatibility with modern and classic gasoline passenger vehicles, including carbureted, two-stroke, and port-injected engines, makes Chevron Techron High Mileage notably versatile. Its deposit-removal claims target gum and varnish while corrosion inhibitors protect metal fuel-system components, giving owners of vehicles over 75,000 miles both cleaning and protection goals.

The 12-ounce bottle combines fuel-system cleaning with corrosion protection, so the stated use goes beyond removing deposits alone. Chevron says it removes gum, varnish, and other deposits that can rob efficiency, connecting cleaning to its fuel-economy aim. Its specified range covers cars, light trucks, and SUVs, including classic vehicles and several engine types; that breadth helps owners with older or less-common gasoline setups assess relevance without assuming diesel compatibility.

Skip it if you need one treatment for gasoline and diesel engines; Gumout Multi-System Tune-Up lists gas, diesel, and ethanol use.

This is a fit for owners of high-mileage gasoline cars, light trucks, or SUVs, especially classic or carbureted vehicles. Its listed compatibility is gasoline-specific, so diesel owners should look to an additive that explicitly includes diesel engines.

Listed on Amazon as: Chevron Techron High Mileage Fuel System Cleaner, 12 oz, Pack of 1

#5 · Concentrated Cleaner

5. Red Line SI-1 Cleaner

• Size: 15 Fl Oz (Pack of 2)

Best for: Concentrated injector and deposit care.

Why it ranks #5: The concentrated 15-ounce formula cleans injectors, carburetors, valves, and combustion-chamber deposits, and is described as supporting efficient fuel burn.

Red Line SI-1 combines a concentrated detergent blend with a synthetic upper-cylinder lubricant, giving its fuel-system cleaning a stated lubrication component. It targets injectors, carburetors, valves, and combustion-chamber deposits, including GDI injectors, while also claiming improved gasoline stability and reduced gum and varnish buildup.

The 15-ounce SI-1 treatment uses high- and low-temperature detergents, which Red Line associates with cleaning deposits across injectors, carburetors, valves, and combustion chambers. Its compatibility with all forms of injectors, including GDI, is useful for owners of direct-injection gasoline vehicles. A synthetic upper-cylinder lubricant adds another stated function, while the product also claims to reduce gum and varnish formation. The listing identifies a two-pack but does not state a per-tank dose.

Skip it if you need a listed dose for straightforward tank planning; Chevron Techron High Mileage describes its vehicle range and cleaning targets.

This suits owners seeking concentrated cleaning for injectors, including GDI, alongside upper-cylinder lubrication and deposit prevention. The two-pack provides repeat supply, but the supplied facts omit a per-tank dose for planning each treatment.

Listed on Amazon as: Red Line 60103 SI-1 Complete Fuel System Cleaner, Cleans and Prevents Corrosion in Fuel Systems, Cleans Injectors, Carburetors, Valve and Combustion Chamber Deposits – 15 Ounce (2 Pack)

#6

6. Gumout Multi-System Tune-Up

• Weight: 0.112 oz
• Dimensions: 8 x 8 x 5.5 in

Best for: Multi-fuel engine maintenance.

Why it ranks #6: Its broad cleaner is described as supporting fuel economy while addressing GDI injectors, carburetors, and deposits across gasoline, diesel, or ethanol engines.

Gumout Multi-System Tune-Up lists compatibility with gasoline, diesel, and ethanol engines, giving it a broader fuel-type range than a gasoline-only treatment. It targets GDI injectors and carburetors while aiming to remove deposits and residue, making it relevant to varied vehicles and equipment such as lawn mowers.

The 16-ounce formula combines cleaning across GDI injectors and carburetors with claims to prevent future carbon buildup, connecting current deposit removal with ongoing engine care. Its stated gas, diesel, and ethanol compatibility extends use beyond passenger cars to equipment such as lawn mowers. Gumout also describes the product as a fuel stabilizer and full-system cleaner. The listing does not give a dose, treatment interval, or quantified MPG improvement, so those details cannot guide a precise routine.

Skip it if you need a quantified MPG claim; Hot Shot's Secret Gasoline Extreme lists an economy improvement claim of up to 7.9%.

This suits owners maintaining different fuel types or equipment, including lawn mowers, who want a multi-system cleaner. Buyers focused on a stated mileage figure or precise dosing will find those details absent from the supplied listing.

Listed on Amazon as: Gumout 510011 Multi-System Tune-Up, Fuel Stabilizer Injector Cleaner & Gas Treatment, 16 oz, Full Fuel System Cleaner – Improves Engine Performance, Cleans & Removes Deposits and Residue

#7

7. Lucas Oil High Mileage Treatment

• Weight: 5.6 oz
• Dimensions: 1.6 x 1.6 x 7.5 in

Best for: Small-dose high-mileage upkeep.

Why it ranks #7: This 5.25-ounce high-mileage treatment is positioned for older vehicles, though the supplied product details do not state a specific MPG improvement.

The 5.25-ounce size is the clearest differentiator for Lucas Oil High Mileage Fuel Treatment, giving drivers a compact bottle for a fuel-treatment routine. Lucas Oil identifies this formula for high-mileage use, while its product information links its additive range with fuel efficiency and power; the supplied listing does not specify a treatment rate.

At 1.6 by 1.6 by 7.5 inches and 5.6 ounces, the bottle is relatively compact to keep with vehicle-care supplies. Its high-mileage designation gives owners of older vehicles a specific treatment category, but the listing provides no dose, compatibility range, or cleaning ingredients to guide a detailed maintenance schedule. Lucas Oil’s general company information discusses additives for fuel efficiency and power, so treat those as brand-level context rather than a quantified promise for this individual bottle.

Skip it if you need a stated dose or detailed cleaning claims; Chevron Techron High Mileage specifies deposit removal and corrosion protection.

This suits a driver seeking a small Lucas Oil high-mileage fuel-treatment bottle for routine vehicle care. The listing is brief, so buyers who need a specified dose, compatibility details, or a defined cleaning mechanism should choose a product with those facts stated.

Listed on Amazon as: Lucas Oil 5.25 Oz. High Mileage Fuel Treatment – 1 Each

#8

8. K&N Performance+ Octane Booster

• Weight: 15.2 oz
• Size: 16 oz

Best for: Knock-and-ping focused drivers.

Why it ranks #8: The 16-ounce bottle treats up to 18 gallons and cleans injectors, but its main stated purpose is octane and performance rather than mileage.

Treatment for up to 18 gallons gives K&N Performance+ Octane Booster a clear full-tank use case. Added during a gas fill-up, it is intended to raise octane and reduce knocks, pings, and hesitation, while also cleaning internal fuel-system parts and remaining safe for catalytic converters and oxygen sensors.

The 16-ounce bottle treats up to 18 gallons, which gives buyers a stated capacity to match against a fill-up. Its octane-boosting purpose addresses detonation-related knocks, pings, and hesitation, while injector-cleaning claims add fuel-system maintenance to the same application. K&N also specifies safety for catalytic converters and oxygen sensors, useful context for owners concerned about those components. This is an octane-focused treatment rather than a listing that quantifies a mileage gain.

Skip it if you prioritize a stated MPG gain over octane and knock control; Hot Shot's Secret Gasoline Extreme lists an economy claim up to 7.9%.

Choose this when octane support and reduced knocking are the priority, with injector cleaning as an added function. It fits a tank up to the stated 18-gallon treatment capacity; buyers seeking a quantified MPG claim should compare other listings.

Listed on Amazon as: K&N Performance+ Octane Booster: Boosts Octane and Improves Engine Performance, 16 Ounce Bottle Treats up to 18 Gallons, 99-2020

#9

9. STP Octane Booster

• Weight: 4.9 oz
• Dimensions: 1.5 x 2.3 x 8 in

Best for: Gasoline power-restoration routine.

Why it ranks #9: This 5.25-ounce gasoline treatment is described as cleaning the intake and restoring power, with no specific fuel-economy claim in the supplied details.

STP combines MMT and synthetic technology to boost octane and clean the fuel intake system, targeting drivers who want both functions in a gasoline treatment. The listing says it can help restore lost power and acceleration during regular fill-ups, and identifies cars and trucks as compatible applications.

This 5.25-ounce treatment is poured directly into the gas tank, making its application part of a regular fill-up or maintenance routine. STP’s MMT and synthetic technology is associated with octane boosting and fuel-intake cleaning, while the product description connects those functions with restoring lost power and acceleration. The stated vehicle fit is gasoline-engine cars and trucks. No tank capacity or treatment rate appears in the supplied details, limiting how precisely a buyer can plan dosing.

Skip it if you need an explicit gallons-treated figure; K&N Performance+ Octane Booster states coverage of up to 18 gallons.

This is aimed at gasoline car and truck owners who want octane support and intake cleaning in a tank-added treatment. The supplied details do not state capacity per dose, so it is less suited to buyers who need exact tank coverage.

Listed on Amazon as: STP Octane Booster for Gasoline Fuel Additive, Restore Lost Power, 5.25 oz

#10

10. STP Octane Booster 12-Pack

• Weight: 4.8 oz
• Dimensions: 2.27 x 1.45 x 7.86 in

Best for: Capless-system octane treatment.

Why it ranks #10: The 12-pack supplies repeated octane-boosting treatments, but its stated focus is raising octane and restoring power rather than improving gas mileage.

Compatibility with capless gasoline systems distinguishes this STP Octane Booster for drivers whose vehicles use that filler design. Each listed 5.25-ounce bottle combines MMT and synthetic technology to raise octane and clean the fuel intake system, with the stated aim of restoring lost power and acceleration.

STP specifies compatibility with all gasoline engines, including capless systems, helping owners of those vehicles identify a listed option. The two-in-one formula pairs octane boosting with fuel-intake cleaning, and the description connects raised octane with reducing knocking and pinging. The product is listed as a 12-pack of 5.25-ounce bottles, which provides multiple individual bottles for recurring use. The supplied details do not state gallons treated per bottle or a specific fuel-economy gain.

Skip it if you want a single bottle with stated full-tank capacity; K&N Performance+ Octane Booster treats up to 18 gallons.

This fits gasoline-vehicle owners with capless fillers who want recurring octane and intake-cleaning treatments. The multi-bottle listing suits repeat use, but it does not provide a per-bottle gallons-treated figure or a mileage-improvement number.

Listed on Amazon as: STP Octane Booster, Fuel Intake System Cleaner, Bottles, 5.25 Fl Oz, Pack of 12