Do Fuel Additives Work?

Store shelves are littered with fuel additives that claim to provide a number of benefits, including…

• Increased fuel economy
• Smoother engine operation
• Reduced emissions
• Extended engine life
• Maximum horsepower

Do fuel additives work, though?

A quick Google search reveals multiple articles that claim they don’t. There must be a good reason so many people regard fuel additives with skepticism.Amsoil Pi performance improver

One reason is, while most motorists expect to experience the benefits promised by fuel additives immediately, it takes several tanks of treated fuel before most additives provide any noticeable performance improvement. That doesn’t bode well in a society used to getting what it wants, when it wants it.

Engine condition plays a vital role in additive performance

Here’s what often happens.

Over time, performance-robbing deposits form on your engine’s fuel injectors, valves and in the combustion chamber. Today’s injectors are highly engineered to tight tolerances, and even minute deposits interfere with the spray pattern and reduce power and fuel economy. The problem is especially pronounced in high-pressure common-rail (HPCR) diesel engines and in direct-injection engines that locate the injectors in the combustion chamber, exposed to intense heat. Eventually, you notice a reduction in power, throttle response, fuel economy or drivability. You pick up a fuel additive at the gas station or parts store. “Increases Fuel Economy!” it proclaims. “Outstanding,” you think.

One and done?

But, by the time you pull up your driveway, nothing has changed. Or again the next day after you arrive at work. What went wrong?

Technically, nothing. You likely bought an inexpensive additive that contains minimal cleaning agents. If you continue to buy the additive and use it with every tank of fuel, maybe over some period of time – could be weeks to months – you’ll experience a slight up-tick in power, fuel economy or drivability. Then you can continue to use the additive to maintain engine performance. The additive did, indeed, work and it did live up to its performance claims. It just didn’t do it quickly or dramatically enough.

fuel injector patternAdditive concentration matters

It takes a fuel additive formulated to the correct concentration to deliver immediate results. And the fact is, most additives on the market simply don’t contain a sufficient concentration of cleaning agents to provide immediate results.

That’s where AMSOIL is different.

P.i. Performance Improver, for example, is one of the most potent gasoline additives on the market today. It does an excellent job cleaning deposits to improve fuel economy up to 5.7% and an average of 2.3%. It also reduces emissions.

Our technical study provides all the details you could ever want, and probably a few more. Or, simply take a look at the before/after images shown here and you can see the dramatic results after just one tank of fuel treated with P.i.intake valves before and after

Don’t forget the diesel additives

For peak performance, diesel engines need a daily dose of detergent for cleaning and lubricity to protect the injectors and fuel pump while keeping the combustion chamber clean.

And don’t forget Quickshot for your small engines and powersports equipment. It cleans performance-robbing deposits, stabilizes fuel during short-term storage and fights ethanol problems.

So, yes, fuel additives do work – if you use the right ones.


  1. I am sorry but before I used amsoil fuel additive I was getting 17 mpg in my 2013 Honda CRV which I thought was terrible. After I added amsoil I now get between 10 and 13 mpg. I am using the same gas station as I have always used.

  2. If you consistently use a Top Tier gasoline with additives blended for the local climate, a new engine will stay clean and run properly. Letting an older engine get full of gook over the years will not be cured by ANY additives, including the Amsoil PI that is being touted here by yet another pyramid scheme distributor.

    1. Hi Terri,

      Thanks for the input. Isn’t it great to live in a country where you don’t have to buy a product from a company you don’t like if you don’t want?

      Thanks for reading.


  3. Add a pint of automatic transmission fluid to each tank of gas – worked like a damn on the farm. Kept spark plugs and injectors clean

    1. i would not think ur catalytic converter would like having all that OIL passing thru it… a friend had a car that used a “little” oil, not amsoil, it eventually plugged up, car could not be driven anymore… engine idled, but could NOT reach 20 mph… also i had a car that had 3 bad valve seals, as it turned out, used VERY little oil, way back in ’79… was brand new, & it fouled out the plugs… gave a bottle of P.I. 2 a friend, who used it in his newer honda… was surprized… seemed 2 give him better mpg… imagine that…

    1. Hi Nick,

      True, fuel additives won’t clean the back of the intake valves in a GDI engine, but they still clean the fuel injectors and combustion chamber, which helps improve fuel economy. Check out our white paper on AMSOIL P.i.. Scroll to page 7 and you’ll see the results of testing performed on a VW Jetta GDI. AMSOIL P.i. improved fuel flow an average of 2.3%.

      Thanks for reading.

  4. I’ve spoken with so many people who purchase fuel additives, and wonder why they don’t work. Then I ask them what brand they use, and where they get it from. They say they get it from the dollar store. I tell them I’m sorry, but the additives they sell at the dollar store just won’t cut it, unfortunately.

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