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Restore Horsepower

AMSOIL is known for its awesome synthetic line of engine oils. But did you know AMSOIL also has one of the best fuel additives for gasoline engines on the market with dyno and lab-proven results?

Why Use Fuel Additives?

There's no magic trick or a cure-all product when it comes to maintaining your car or truck.

You spend hours every few months, washing, waxing, buffing, and polishing all the paint, glass, and chrome to keep the exterior looking great going down the road, but what about running great? That's where AMSOIL's P.i. Performance Improver Gasoline Additive comes in. It deep cleans so your engine is treated the same way as your paint job.


AMSOIL P.i. Performance Improver Gasoline Additive

AMSOIL P.i. is a potent gasoline performance improver with a concentrated detergent that aggressively cleans stubborn, power-robbing deposits from injectors, valves, and the combustion chamber. Effective in port and direct injection systems. Bottle compatible with capless fuel systems.

Cleans the entire fuel system in one tank of gasoline. For use with cars and trucks.

Treats up to 30 gallons. Add the entire bottle to the tank at fill-up. For best results, clean your fuel system with P.i. every 4,000 miles (6,400 km).

Do not use with diesel fuel, E85, or 2-stroke mixed fuel.

See the Product Data Bulletin for full details.



  • Helps keep valves clean and moving freely.

  • Aggressive additives attack the most common forms of engine deposits and limit their effects.


  • P.i. removes deposits and keeps injectors functioning as they should.

  • Testing shows P.i. restored GDI fuel injectors to a 100% flow rate after one tank of fuel.2


  • Third-party testing demonstrated the performance of P.i. using a 2016 Chevrolet* Silverado* with 100,616 miles on the odometer.

  • Following a single treatment with P.i., the truck measured an incredible 14% improvement in horsepower.1

Check out this video to learn more about AMSOIL P.i.!

Just One Bottle:

  • Restores up to 14% horsepower1

  • Restores GDI fuel injectors to 100% flow rate after one tank of fuel2

  • Improves fuel economy

  • Reduces the need for costly higher-octane fuel

  • Helps prevent carbon rap

  • Controls pre-ignition knock

  • Compatible with capless fuel systems

1Based on third-party testing in a 2016 Chevrolet* Silverado* 1500, 5.3L V-8 GDI with 100,616 miles, using one tank treated with AMSOIL P.i. Actual results may vary. 2ASTM D5598(M) – 2013 Buick Regal test vehicle.


Check Out AMSOIL's Full Line of Fuel Additives

AMSOIL has additives for both diesel and gasoline applications.

Click or tap the image for your application!


AMSOIL has been the market leader in synthetic lubricants since its beginning in 1972 when AMSOIL 10W-40 Synthetic Motor Oil become the first motor oil to meet the American Petroleum Institute's service requirements! Click the logo to learn more about AMSOIL!


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