P.i. Performance Improver Gasoline Additive

The #1 Best Selling non-oil product in the Omaha store! And most of that is repeat sales. When I first used the current version I achieved a stunning 50 more miles from a tank of gas. This product restores lost performance which typically a professional injector cleaning procedure is used which costs 10X what this costs.

  • Restores up to 14% horsepower
  • Restores GDI fuel injectors to 100% flow rate after one tank of fuel
  • Improves fuel economy
  • Reduces need for costly higher-octane fuel
  • Helps prevent carbon rap
  • Controls pre-ignition knock
  • Compatible with capless fuel systems

fuel additive for injector cleaningAMSOIL 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, E85 or 2-stroke mixed fuel.

Printable Product Data Sheet

Download PDFProduct Datasheet

Untreated Fuel Leads to Poor Engine Performance

A vehicle demonstrates its best efficiency and engine performance when it is new. As the engine ages, its performance suffers from gasoline fuel-generated deposits that form on the fuel injectors, intake valves and combustion chamber. Additives are required to control deposit formation.

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  • 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

Horsepower gains after injector cleaning


Today’s fuels, however, lack sufficient treatments of either enough additives or high quality additives. Fuel system deposits result in the following:

  • Lost fuel economy
  • Lost power and poor throttle response
  • Failed emission tests
  • Poor drivability – surging, hesitation, stalling, rough idle
  • Engine knocking (pinging) and rap
  • Difficult starts

Treated Fuel Delivers Maximum Performance

AMSOIL P.i. Performance Improver Gasoline Additive is the most potent gasoline additive available today. As a concentrated detergent, it is unsurpassed in cleaning combustion chamber deposits, intake valve deposits and port fuel injector deposits. AMSOIL P.i. helps maintain peak engine efficiency, fuel economy, power and drivability in newer low mileage engines. In engines with accumulated deposits, testing showed AMSOIL P.i. provided the following clean-up benefits after only one tank of gasoline:

  • Improves fuel mileage an average of 2.3% and up to 5.7%
  • Reduced emissions
    • hydrocarbons (HC) up to 15%
    • carbon monoxide (CO) up to 26%
    • nitrous oxides (NOx) up to 17%
  • Restored power and performance
  • Reduced need for costly higher octane fuel
  • Reduced noise from carbon rap and pre-ignition
  • Better drivability
  • Smoother operation

AMSOIL P.i. works as an ?emissions passer.? It is ideal for use prior to emissions inspections.

Unsurpassed Deposit Clean-up

Port Fuel Injector Deposits form after the engine has been shut down and there is no gasoline flowing through the injectors. During this ?hot soak? period the injectors heat up and the gasoline remaining in the injectors degrades and forms deposits. This can happen very quickly with the use of poor quality gasoline and short trip driving. Because the clearances within the injectors are extremely tight and injectors must deliver precise amounts of ?atomized? fuel, even small amounts of deposits can cause injectors to malfunction. Fuel flow is reduced and spray patterns are disrupted, decreasing engine efficiency, power and fuel economy, while increasing exhaust emissions.test method CARB


Intake Valve Deposits form on the intake side or back side of the valves. As deposits increase, they restrict airflow and alter airflow patterns in the cylinder. The deposits disrupt the balanced air/fuel ratio by momentarily absorbing and releasing fuel, and they can cause valve sticking by getting in the way of the valve stem and guide. Deposits also restrict proper seating, and the valves may be burned. Intake valve deposits cause lost engine power, increased emissions, poor engine efficiency and potential valve failure.


Combustion Chamber Deposits form on the top of the pistons and on the cylinder heads. They increase compression and absorb heat during combustion to later release it during the intake cycle. In some engines with tight squish domes, combustion chamber deposits cause the piston to actually hit the cylinder head. This is referred to as combustion chamber deposit interference or ?carbon rap.? Combustion chamber deposits also flake off as they get large, and these flakes can get trapped between the valves and valve seat, resulting in compression loss, difficult starting and rough idle.

Higher compression and stored heat cause increased intake fresh charge temperatures and the increased likelihood of pre-ignition ?knock? or ?pinging? when the fuel spontaneously combusts prior to spark ignition. This increases emissions and may cause engine damage. Many of today’s cars have ?knock? sensors that adjust spark timing to prevent knock.

Although audible knock is controlled, power is lost from retarded timing. Higher octane fuels of 4-5 octane numbers can be used to help prevent knock, an effect called ?octane requirement increase.?As a vehicle ages, more-expensive,
higher-octane fuel is needed to keep it operating at peak performance. By cleaning combustion chamber deposits, knock is controlled, power is restored, fuel economy increases and higher-octane fuels are less necessary for peak performance.


Maximum Fuel Economy

AMSOIL P.i. maximizes fuel efficiency by dissolving and removing fuel system deposits and other contaminants for improved power and overall performance.



Treat one full tank of gas up to 20 gallons with one bottle of P.i. For very large gas tanks, partially fill to 40 gallons and treat with two bottles of P.i. Using more than two bottles per treatment is not recommended. Treat gas every 4,000 miles of service (or 100 hours for marine, stationary and off-road gasoline-powered engines). P.i. helps pass emission tests by running one tank of treated fuel through the engine prior to testing. Safe for use with catalytic converters, oxygen sensors, oxygenated gas and 10 percent ethanol blended gas. Not recommended for two-cycle engines.

DANGER: Combustible. Harmful or fatal if swallowed. Harmful if inhaled. Skin and eye irritant. Read precautions on container before use.

Customer Comments:


Use a part of regular service.

By  RICKY,  a  Verified Buyer  from  Conway, SC  on  January 18, 2024
I have been using this additive for several years and am a fan. Just like with my MC, I noticed our HEMIs ran a little rough at times, since we moved to SC. Professional techs explained the issues we were having was most likely due to the poor fuel quality in this area. I use one bottle at every oil change. And one between 3 and 4K miles. I haven’t had the hesitation issue, since I started using this additive.

Better gas mileage than prior

By  DAVE,  a  Verified Buyer  from  Wilmington, Delaware  on  January 14, 2024

Started using this product every 5K. I don’t know if it’s my head, but my wife is getting better gas mileage as a result.. the idle also has smoothed out when you come to a stop sign or red light.

PI performance improver

By  RODNEY,  a  Verified Buyer  from  Vermillion S.D.  on  January 11, 2024

I had a friend who’s truck didn’t like to start in cold weather, he even tried new plugs and wires to no avail. After using just one treatment he said the problem finally went away great product . Thanks guys

Great product!

By  GARY,  a  Verified Buyer  from  Iowa  on  January 06, 2024
I used the Amsoil gasoline additive in my Escalade and Dodge pickup. It brought the Escalade to life and gave my pickup a newfound boost of power. I use one bottle with each tank of gas. My miles per gallon has increased and gave me a quick needed boost. I would definitely recommend this product. I will be using it also in my Harley next spring.

P.i. Performance Improver Gasoline Additive
By Moe 1/10/2017

from San Antonio TX

I’ve been using Amsoil for years great products especially this fuel additive see a difference in vehicle performance on first fill up

Bottom Line

Yes, I would recommend this to a friend