Declines in engine performance could stem from your fuel. Modern ultra-low sulfur diesel (ULSD) strips away the lubricity and affects the cetane that diesel engines depend on, and standard pump gasoline leaves behind carbon deposits on injectors, valves and pistons with every fill-up.
Fuel injector deposits can impact fuel economy, and burning more fuel costs real money at the pump. The right fuel additive cleans, boosts cetane, restores lubricity and protects your fuel pump. Some products, like Diesel Extreme, can deliver up to 7.3% more miles per gallon (MPG). For gas engines, Gasoline Extreme improves MPG by up to 7.9%.
Hot Shot’s Secret products are Powered By Science and backed by the best money-back guarantee in the industry. Below, we break down the best fuel additives for every situation, whether you drive a diesel, have a gas engine, tow heavy loads or face harsh winters.
What Makes a Fuel Additive the Best?
Not all fuel additives are created equal. The best diesel fuel additives — and options for gasoline engines — come down to a few key factors that separate real performance from marketing hype:
- Active ingredient quality: For gasoline, polyetheramine (PEA) dissolves hard carbon deposits. If you drive a diesel, you need internal diesel injector deposit (IDID) detergents that target waxy buildup inside high-pressure common rail (HPCR) injectors. Lubricity agents replace what ULSD refining strips away.
- Concentration level: Concentrated formulas pack more active ingredients into every ounce. More concentration means better cleaning power and stronger cetane boosts.
- Multi-functionality: The best products clean, protect, enhance performance and address cold-weather issues in one bottle.
- Compatibility: The right product is safe for all emissions systems, including catalytic converters, O2 sensors, diesel particulate filters (DPF) and every injector type. Ashless formulas prevent buildup.
- Third-party testing: Brands that publish ASTM test results earn trust by proving that their products work.
- Money-back guarantee: A guarantee-backed fuel additive shows the manufacturer’s confidence in the results.
Best Everyday Diesel Additive: Hot Shot’s Secret Everyday Diesel Treatment (EDT)
Hot Shot’s Secret Everyday Diesel Treatment (EDT) is the best diesel fuel treatment for drivers who want consistent protection, improved fuel economy and a cetane boost at every fill-up. The treatment provides all these benefits without waiting for a deep-clean interval.
ULSD processing strips natural lubricity, leaving fuel pumps and injectors vulnerable. Infused with LX4 Lubricity Extreme, EDT can boost fuel lubricity and reduce wear scars by up to 159 microns, helping to accommodate the Engine Manufacturers Association (EMA) recommendation of a maximum wear scar of 460 microns.
Here’s what makes EDT the best diesel additive:
- Boosts cetane for stronger, cleaner combustion
- Increases lubricity by 26% to protect fuel pumps and injectors
- Cleans injectors and prevents deposit buildup
- Disperses moisture using a non-alcohol demulsifier
- Inhibits rust and corrosion in the fuel system
- Stabilizes fuel during storage
For drivers looking for the best additive to remove water from diesel fuel, EDT’s non-alcohol demulsifier safely disperses moisture without causing fuel system damage. EDT also prevents injector failure, corrosion and microbial growth resulting from water contamination.
Real-world testing shows EDT delivers up to 7.3% improvement in fuel mileage. Use 1 ounce per 25 gallons for standard maintenance or 2 ounces for a performance dose. A 16-ounce bottle treats between 200 and 400 gallons, depending on your dosage.
EDT works in diesel pickup trucks, semis, farm equipment and RVs. Use it at every fill-up to turn standard pump diesel into premium diesel. The ashless formula is emissions-system safe and complies with federal low-sulfur content requirements, so it won’t void your warranty or trigger DPF issues.
While EDT handles daily maintenance, you can also use it alongside Hot Shot’s Secret Diesel Extreme, which delivers periodic deep cleaning.
Best Diesel Fuel Additive for Deep Cleaning: Hot Shot’s Secret Diesel Extreme
For a deep-clean diesel treatment that removes both internal and external injector deposits, Hot Shot’s Secret Diesel Extreme is the most concentrated formula on the market — a six-in-one additive that cleans the entire fuel system. As such, Diesel Extreme is the best diesel injector cleaner available.
Most diesel additives cannot remove IDIDs. Standard cleaners target external diesel injector deposits (EDID) but leave internal buildup untouched. Diesel Extreme dissolves both types of buildup, restoring spray patterns and combustion efficiency.
In addition to removing both deposits, here’s what makes Diesel Extreme the best diesel fuel injector cleaner:
- Boosts cetane up to seven points for better combustion efficiency
- Improves lubricity to protect pumps and injectors
- Stabilizes fuel for long-term storage
- Disperses moisture with a military-grade, non-alcohol demulsifier
- Inhibits rust and corrosion throughout the fuel system
The seven-point cetane boost means more power, improved MPG, smoother starts and fewer DPF regeneration cycles. Diesel Extreme works in all diesel engines, including Cummins, Duramax, Powerstroke, semis, RVs and farm equipment. A 16-ounce bottle treats 40 gallons, and we recommend using it once every 6,000 miles.
Noticing black smoke on startup, reduced power or declining fuel economy? Those are signs of injector deposit buildup. One treatment of Diesel Extreme every 6,000 miles keeps your injectors clean and your system performing at peak. Stack it with EDT at every fill-up in between for the ultimate diesel care routine.
As one of the best DPF cleaner fuel additives, Diesel Extreme also reduces soot load by improving combustion efficiency, which means fewer forced regenerations and less strain on your emissions system.
Best Fuel Additive for Gasoline Engines: Hot Shot’s Secret Gasoline Extreme
For gasoline engines, Hot Shot’s Secret Gasoline Extreme is the best fuel system cleaner. It uses PEA detergent technology to clean injectors, valves, pistons and combustion chambers in a single tank. It also offers improvements in MPG of up to 7.9% as documented in user testing.
The active ingredient is PEA, the most effective detergent for dissolving hard carbon deposits. PEA separates professional-grade cleaners from low-cost options.
Use Gasoline Extreme to clean:
- Fuel injectors (restores proper spray patterns)
- Intake valves (dissolve carbon that causes a rough idle)
- Combustion chambers (removes performance-robbing deposits)
- Rings and pistons
- Upper cylinders
Gasoline Extreme is also infused with LX4 Lubricity Extreme, which serves as an upper-cylinder lubricant. The formula reduces wear on critical components and contributes to the measurable fuel economy gains.
This additive is ideal for any gas-powered vehicle, especially older or high-mileage engines. If you’re experiencing rough idle, hesitation, or sluggish performance, Gasoline Extreme addresses both dirty injectors and carbon buildup on intake valves — the two most common culprits. Use it as a periodic treatment, or after switching fuel sources or extended storage.
Best Fuel Additive for Fuel Pump and Injector Protection: Hot Shot’s Secret LX4 Lubricity Extreme
If your primary concern is protecting your fuel pump and injectors from the damaging effects of low-lubricity fuel, Hot Shot’s Secret LX4 Lubricity Extreme delivers the highest-lubricity performance available. As a stand-alone premium lubricity additive designed for both ULSD diesel and gasoline, LX4 is the best diesel fuel lubricity additive you can buy. It’s the same technology infused into EDT and Gasoline Extreme, now available in concentrated form for maximum protection.
ULSD refining strips oxygen and nitrogen compounds that naturally lubricate fuel components. Without lubricity, pumps and injectors suffer metal-on-metal wear. Significant pump failures pose a real risk, especially in HPCR systems and Common Rail Pump, 4th Generation (CP4)-equipped trucks.
LX4 reduces wear scars by up to 56% in ASTM D6079-22 testing on unadditized ULSD. That exceeds the U.S. Government ULSD specification of 520 microns and the EMA’s recommended maximum of 460 microns.
LX4 is ideal for ULSD diesel drivers who want maximum fuel pump and injector protection, gas engine upper-cylinder lubrication and anyone running equipment in high-stress conditions — fleet operators, farmers, semi drivers and owners of Duramax, Powerstroke, or Cummins trucks (especially CP4-equipped models).
LX4 is 100% compatible with Diesel Extreme, EDT and Gasoline Extreme — stack it on top for additional protection during heavy towing, hauling, or extended intervals. It contains no alcohol or harmful solvents, making it safe for emissions systems, catalytic converters and O2 sensors.
Best Diesel Fuel Additive for Cold Weather: Hot Shot’s Secret EDT+ Winter Defense
For cold-weather diesel protection, Hot Shot’s Secret EDT+ Winter Defense is a seven-in-one formula that prevents diesel fuel from gelling and icing down to extremely low temperatures while delivering all the cetane, lubricity and cleaning benefits of our original Everyday Diesel Treatment additive.
Since diesel fuel contains paraffin wax, it can crystallize and clog filters below the cloud point, preventing cold starts. EDT+ Winter Defense uses a wax modifier to keep fuel fluid and includes a deicer to prevent fuel line icing.
Here’s what you can expect from EDT+ Winter Defense:
- Prevents gelling and icing down to -40°F
- Boosts cetane for easier cold starts
- Increases lubricity with LX4
- Cleans injectors and prevents deposit buildup
- Disperses moisture
- Inhibits rust and corrosion
- Stabilizes fuel
EDT+ Winter Defense allows fuel to travel through filters 20°F below cloud point, keeping your engine running when temperatures drop. Switch from standard EDT to EDT+ Winter Defense when temps fall below 32°F, and continue using Diesel Extreme every 6,000 miles through winter for deep cleaning.
This formula is essential for all diesel drivers in cold climates. Don’t wait until your fuel gels. Anti-gel treatments must be proactive, not reactive.
Which Fuel Additive Is Right for Your Engine?
Here’s a quick-reference guide to match your needs with the right product:
- Deep diesel injector cleaning (IDID removal): Use Diesel Extreme every 6,000 miles.
- Daily diesel maintenance and MPG improvement: Use Everyday Diesel Treatment (EDT) at every fill-up.
- Gas engine cleaning and performance restoration: Use Gasoline Extreme periodically or as needed.
- Maximum fuel pump and injector protection: Use LX4 Lubricity Extreme at every fill-up, or stack with other products.
- Cold-weather diesel protection (anti-gel): Use EDT+ Winter Defense at every fill-up below 32°F.
For most diesel drivers, the ideal stack is Diesel Extreme every 6,000 miles with EDT at every fill-up or EDT+ Winter Defense in cold months. Add LX4 for CP4 engines or lubricity issues. For gas drivers, Gasoline Extreme is the best starting point.
Do Fuel Additives Actually Work?
Yes, fuel additives work, provided they contain the right active ingredients in sufficient concentration. The most effective diesel additives use specialized detergents to remove injector deposits, cetane improvers to enhance combustion, and lubricity agents to protect fuel system components. For gasoline engines, PEA is the gold standard detergent for cleaning injectors and intake valves.
Not all additives are effective. Low-quality products rely on fillers and diluted formulas. Concentration matters — the type of detergent determines whether a product can remove IDIDs, which standard cleaners cannot address. ASTM testing standards provide verifiable proof that a product works. Properly formulated, ashless additives are safe for all emissions systems and will not void warranties.
Every Hot Shot’s Secret formula uses ingredient ratios that are independently tested and scientifically validated. The results speak for themselves. If they don’t perform as mentioned, you get your money back.
Frequently Asked Questions About Fuel Additives
Learn more about fuel additives from these questions we commonly receive:
Do any fuel additives actually work?
Yes. Fuel additives with the right active ingredients — like PEA for gasoline or IDID detergents for diesel — deliver measurable improvements in cleaning, lubricity and performance when used as directed.
What is the best fuel additive on the market?
The best fuel additive depends on your needs. Diesel Extreme deep cleans injectors. EDT handles daily maintenance. Gasoline Extreme cleans gas engines. Each formula is scientifically formulated, independently tested and backed by a money-back guarantee.
What is the #1 fuel injector cleaner?
For diesel injectors, Diesel Extreme uses IDID-specific detergents that target internal deposits standard cleaners can’t touch. For gasoline injectors, Gasoline Extreme uses PEA detergent — the most effective chemistry available.
What is a top-tier fuel additive?
“Top Tier” is a fuel certification standard, not a product. Fuel additives provide additional cleaning and protection beyond what pump fuel offers.
Can fuel additives damage a fuel pump?
Properly formulated, alcohol-free additives will not damage a fuel pump — they protect it. LX4 Lubricity Extreme, for example, extends pump life by reducing metal-on-metal wear. Low-quality additives with harsh solvents or alcohol can cause harm, which is why choosing a reputable brand matters.
What cleans your fuel pump?
Depending on your fuel type, Diesel Extreme or Gasoline Extreme cleans the fuel system, including the pump inlet. LX4 Lubricity Extreme protects the pump by reducing wear. Use both together for comprehensive protection.
How to Use Fuel Additives for Best Results
Keep these tips in mind when using your fuel additives:
- Add at fill-up, before pumping: Pour the additive into your tank first so the incoming fuel mixes it evenly throughout.
- Follow the treat ratio: EDT uses 1 ounce per 25 gallons for standard use or 2 ounces per 25 gallons for a performance dose. Diesel Extreme uses 16 ounces per 40 gallons. Overdosing is wasteful and can affect combustion balance.
- Use Diesel Extreme every 6,000 miles: Then use EDT or EDT+ Winter Defense at every fill-up in between.
- Switch to EDT+ Winter Defense when temps drop below 32°F: Anti-gel needs to be proactive, not reactive. Once fuel has gelled, it’s too late.
- Stack LX4 for additional protection: LX4 is compatible with all Hot Shot’s Secret fuel additives. Add it on top of EDT or Gasoline Extreme during high-stress intervals, such as towing or heavy loads.
- Use consistently: One treatment restores performance. Consistent use prevents problems from recurring.
The Bottom Line on Best Fuel Additives
The difference in fuel additives lies in ingredients, concentration and engineering that determine whether a product actually works or just takes up shelf space. Hot Shot’s Secret offers a complete lineup for both diesel and gasoline engines, built around real-world performance data and backed by science. Whether you need a deep clean, daily maintenance or lubricity protection, there’s a right product for every use case. Each formula is emissions-system safe, ASTM-tested and engineered to deliver measurable results.
Ready to protect your engine and get more out of every gallon? Browse the full fuel additive lineup from Hot Shot’s Secret and find the right treatment for your engine.