Customer Ratings & Reviews

I've driven 150,000 km using only this product every year after winter to clean and maintain my injectors. My engine still sounds like it did the day I bought it from the dealership. It works wonderfully.

Good to use when doing a oil change to help the intake clean

Use it every thing I take a long trip

I purchased three products from AMSOIL, The Upper Cylinder Lubricant Corrosion Inhibitor, The DOMINATOR® Octane Boost, and The P.i.® Performance Improver Gasoline Additive I added all three to a full tank but, prior to doing this, I had filled the tank with Top Tier Fuel for this test Shortly after I took a ride, at first, I noticed nothing, but the very next day I put twenty miles on her, and that is when I noticed she ran quieter, and that the pick-up was back I highly recommend this product for older vehicles, and I want you to know, that these products are not a gimmick Check it out for yourself

I added this to my 2021 Camaro and so far it's doing a good job. I will need to update later if it helps with the gas mileage at all.

I had a check engine light for anti-knock sensor on my 2005 1500hd sliverado. I’m thinking I had a dirty fuel injectors and this product cleaned them. Thank you.

Been using the products for years! Would highly recommend any of the products!

I have a 2011 6.2 raptor. My mileage has been between 10.5-11.5 on average. Really depends if I’m doing 63-65 or 70+ MPH. Now I will say that I haven’t used a few additive in my truck in a while. It was time to get some more oil so I decided to get some PI to go along with it. Not even within that day, after putting the additive in my fuel, I considerably noticed better throttle response. On top of that I also was doing the math and my mileage went up to 13.1 miles per gallon on average. I am completely blown away especially right now with gas being over $4 a gallon.

Great product.

Le moteur tourne mieux plus égale aussi à reprendre à la prochaine commande pour tous mes véhicules

I've tried several fuel system cleaner products in the past, but never noticed any changes. But the AMSOIL P.I. Improver actually works! I use it in all my vehicles, 2021 GMC Yukon Denali, 2018 Jeep JL Wrangler Rubicon, and 2015 F150 w/5.0 Coyote Engine. I first put it in my son's truck shortly after we purchased it with 148,000 miles to clean up all the years of gunk. Poured a bottle in before filling up a tank of gas just before a long highway trip that ran it down to empty. We noticed a bump in horsepower as well as a bump in MPG. This is part of our regular maintenance in all our vehicles, every 4,000 miles, in trying to get our vehicles running better than new.

I bought a used 2021 Subaru Ascent with 70,000 miles. I decided to switch over to AMSOIL products to improve and prolong the life of my car. I'm so glad I did. I was only getting like 17 miles/gallon before I switched to this AMSOIL product. I have now ran two bottles of the AMSOIL Performance Improver Gasoline Additive through the fuel system. Last week I went on a road trip visitibg different lakes in West Virginia. 1/2 the time I was on back roads which were hilly and curvy and the other half was interstate driving. I was actually shocked to see my MPG jump from 17 to 26.5 The next time I place an order I will be sure to get a few bottles of AMSOIL Performance Improver Gasoline Additive. I highly recommend all AMSOIL products. I've also switched to AMSOIL motor oil and CVT transmission fluid and my Subaru thanks me for it! Thank you AMSOIL!

Put two of these in a 36 gal tank at fill up after an oil and air filter change. Saw about an 0.5 to 1 gal increase in gas mileage. I think it helped with a rough idle issue that has since not come back after 1,000 miles.

Used for the first time. My vehicle has 180,000 miles and I have used fuel additives periodically but never felt like I saw any benefit. I really got this to get me to the level of free shipping. No change on the tank I ran it through but a .8 MPG increase on the next tank. Both tanks were run over the same highway route within days. I am sold will definitely be getting a bottle with every oil change.

I purchased two bottles of this PI cleaner after reading positive reviews about it. Though I'm not a regular AMSOIL user, I decided to splurge a little and run this "premium" cleaner through my Nissan Rogue since it has high mileage. I filled up the gas tank and added the first bottle of cleaner. I drove the car until the tank was nearly empty, then refueled and added the second bottle. About a quarter of the way through the tank, the car began to run poorly and lacked power. I did some troubleshooting and narrowed it down to a clogged catalytic converter. Now the Rogue has 2 cats, a front one that is integral to the exhaust manifold and a second one that is downstream. Using a boroscope i was amazed to discover the first cat was completely empty and the debris from it was clogging the second converter. I contacted Amsoil and was told there was no way that could be the fault of their product. "It's just a cleaner," I was told. Now both of my converters are trashed, the forward catalytic converter that was empty was just under a year and a half old and the damage the debris did to the aft converter ruined it. So now I am out 2 converters. Maybe it just cleaned too well and carbon broke loose and clogged the cat. I don't know for sure, but I am not using it again.

Wouldn’t change for anything

Excellent product as always

I use this product once a year on my gmc canyon.

Definitely seen a better acceleration response and did notice my gas lasting longer than usual

Help with the idle of my old car