About this item

• Product Overview

  AMSOIL P.i. is a potent gasoline performance improver with 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 entire fuel system in one tank of gasoline. For use with cars and trucks. Treats up to 30 gallons. Add entire bottle to 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 or two-stroke engines.

  See the Product Data Bulletin for full details.

  MAXIMUM DEPOSIT CLEAN-UP

  • Helps keep valves clean and moving freely.
  • Aggressive additives attack the most common forms of engine deposits and limit their effects.

  ---

  REMOVES FUEL-INJECTOR DEPOSITS

  • 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

  ---

  RESTORES HORSEPOWER

  • Third-party testing demonstrated 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

  CLEANS COMBUSTION CHAMBER DEPOSITS

  • Fights combustion chamber deposits to help restore power, control knock, increase fuel economy and reduce the need for higher-octane fuels.
  • Protects against compression loss, difficulty starting and rough idling.
  • Reduces possibility of "carbon rap," when deposit buildup causes the piston to hit the cylinder head.
  • Decreases the possibility of pre-ignition "knock" or "pinging."

  ---

  CAPLESS-COMPATIBLE BOTTLE

  • Bottle is fully 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.

  See the Product Data Bulletin for full details.

• Technical Specifications
  Warranty

  WARRANTY

  Data Bulletin

  Data Bulletins

  SDS

  SDS

  
  
  
• Product Reviews
  4.9 star rating

  Based on 1,147 reviews

  Based on 1,147 reviews

  See all customer reviews

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  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    Great product
    By  TODD,  a  Verified Buyer  on  June 16, 2026

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    I use P.I. In all of my gas powered equipment. Seems to really work well with keeping things clean and stable.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Good gas additive
    By  ALFRED,  a  Verified Buyer  from  Plano, TX  on  June 16, 2026

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    With the worsening quality of fuels getting delivered these days, to keep your fuel system running clean, and prolong your engine life, use this!
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Amsoil gasoline additive
    By  MELVIN,  a  Verified Buyer  from  Fort Macleod Alberta   on  June 10, 2026

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    Great product have had zero fuel issues
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Fuel additive
    By  WILSHIRE,  a  Verified Buyer  on  June 08, 2026

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    Great product
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Added fuel system protection
    By  PHILIP,  a  Verified Buyer  from  South Carolina  on  June 08, 2026

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    I use it once a year. My garage queen sits for extended periods and this product protects and cleans my fuel system for optimal pergormance
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (0) NO (0)
  • 5 star rating
    I will be ordering more soon
    By  DEBBARA,  a  Verified Buyer  from  Chicago   on  June 07, 2026

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    I like the performance it gives my engine & will be ordering more soon
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (0) NO (0)
  • 5 star rating
    Can't have a dirty fuel system
    By  NYmetaldog,  a  Verified Buyer  from  Fairport NY   on  June 02, 2026

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    I've got to be able to take my Terminal Wife to her appointments or to VA to visit our Son's without problems. I'm not taking chances with my cars. This product has the science and correct ingredients to keep my fuel system clean.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    It just works great!
    By  DAVE,  a  Verified Buyer  from  Near Austin TX  on  June 01, 2026

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    We have a 2014 Lincoln Navigator, and an 08 F150. I've been using this at least twice a year on both trucks. I don't track MPG, but I know that both trucks are running smoother than when we got them. In my mind, this is cheap insurance.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    See the difference
    By  WOODY,  a  Verified Buyer  from  Swansboro, NC  on  June 01, 2026

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    You can see the difference in gas mileage when you use this additive.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    PI gas additive
    By  MELVIN,  a  Verified Buyer  from  Alberta   on  May 31, 2026

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    No fuel problems and improved gas mileage
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

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• Highlights

  • Restores up to 14% horsepower¹
  • Restores GDI fuel injectors to 100% flow rate after one tank of fuel²
  • Improves fuel economy
  • Reduces 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.

• Returns

  We offer easy returns for customers. If your product is unused and unopened, you may return it within 30 days for a full refund of the purchase price. View full AMSOIL Return Policy.

• Payments

  We accept Visa, Mastercard, American Express, Discover and PayPal, and provide secure checkout and encrypted payment processing.

• Product Overview

  AMSOIL P.i. is a potent gasoline performance improver with 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 entire fuel system in one tank of gasoline. For use with cars and trucks. Treats up to 30 gallons. Add entire bottle to 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 or two-stroke engines.

  See the Product Data Bulletin for full details.

  MAXIMUM DEPOSIT CLEAN-UP

  • Helps keep valves clean and moving freely.
  • Aggressive additives attack the most common forms of engine deposits and limit their effects.

  ---

  REMOVES FUEL-INJECTOR DEPOSITS

  • 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

  ---

  RESTORES HORSEPOWER

  • Third-party testing demonstrated 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

  CLEANS COMBUSTION CHAMBER DEPOSITS

  • Fights combustion chamber deposits to help restore power, control knock, increase fuel economy and reduce the need for higher-octane fuels.
  • Protects against compression loss, difficulty starting and rough idling.
  • Reduces possibility of "carbon rap," when deposit buildup causes the piston to hit the cylinder head.
  • Decreases the possibility of pre-ignition "knock" or "pinging."

  ---

  CAPLESS-COMPATIBLE BOTTLE

  • Bottle is fully 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.

  See the Product Data Bulletin for full details.

• Technical Specifications
  Warranty

  WARRANTY

  Data Bulletin

  Data Bulletins

  SDS

  SDS

  
  
  
• Product Reviews
  4.9 star rating

  Based on 1,147 reviews

  Based on 1,147 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    Great product
    By  TODD,  a  Verified Buyer  on  June 16, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I use P.I. In all of my gas powered equipment. Seems to really work well with keeping things clean and stable.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Good gas additive
    By  ALFRED,  a  Verified Buyer  from  Plano, TX  on  June 16, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    With the worsening quality of fuels getting delivered these days, to keep your fuel system running clean, and prolong your engine life, use this!
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Amsoil gasoline additive
    By  MELVIN,  a  Verified Buyer  from  Fort Macleod Alberta   on  June 10, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Great product have had zero fuel issues
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Fuel additive
    By  WILSHIRE,  a  Verified Buyer  on  June 08, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Great product
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Added fuel system protection
    By  PHILIP,  a  Verified Buyer  from  South Carolina  on  June 08, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I use it once a year. My garage queen sits for extended periods and this product protects and cleans my fuel system for optimal pergormance
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    I will be ordering more soon
    By  DEBBARA,  a  Verified Buyer  from  Chicago   on  June 07, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I like the performance it gives my engine & will be ordering more soon
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Can't have a dirty fuel system
    By  NYmetaldog,  a  Verified Buyer  from  Fairport NY   on  June 02, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I've got to be able to take my Terminal Wife to her appointments or to VA to visit our Son's without problems. I'm not taking chances with my cars. This product has the science and correct ingredients to keep my fuel system clean.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    It just works great!
    By  DAVE,  a  Verified Buyer  from  Near Austin TX  on  June 01, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    We have a 2014 Lincoln Navigator, and an 08 F150. I've been using this at least twice a year on both trucks. I don't track MPG, but I know that both trucks are running smoother than when we got them. In my mind, this is cheap insurance.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    See the difference
    By  WOODY,  a  Verified Buyer  from  Swansboro, NC  on  June 01, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    You can see the difference in gas mileage when you use this additive.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    PI gas additive
    By  MELVIN,  a  Verified Buyer  from  Alberta   on  May 31, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    No fuel problems and improved gas mileage
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)