Customer Ratings & Reviews

Great product running it in all of my vehicles. Noticed a big difference in the performance of my vehicles. Used to use a different product, now I'm team Amsoil for sure.

I can see a difference after using

I’ve been using Performance Improver for years, currently my 22’ Toyota & 2013 Honda. Improves gas mileage & gives you an engine boost.

I have using it for a while , it does the job

Definitely a notable difference in my 2016 F350 6.2L Flex Fuel. Affordable, quality product that works!

Fuel Mileage increase is noticeable. Lasts a few tanks after.

I always use this on my last empty tank 20 gal fill-up before changing my 2013 Silverado 6.0 gasser's oil. I also use it along with the Upper Cylinder Lubricant too at the same time with good results. I definitely notice my truck running smoother for a pretty good long while afterwards. Give it a shot!

As the product cleans during the tank of gas usage, gradual improvement in performance is noted and definitely is noticeable after running the entire tank of additive containing fuel through. I haven't calculated the actual mpg increase, but it has definitely helped.

Great value for a product that works as advertised.

Car runs 100% better starts instantly in cold weather improved mileage

I couldn't believe how quickly I noticed a difference in performance in less than 100 miles smoother,stronger on a 160k plus Corolla

The AMSOIL Performance Improver Gasoline Additive has improved my gas mileage and keeps the engine running smooth. I use that in between using the Upper Engine Lubricant. I would recommend these products for any vehicle.

Bought a 12 pack, started adding 1 every fill up, checked mileage before and after, maybe 1/2 mile per gallon better. For the cost per bottle, doesn’t justify 1/2 mile per gallon. Sorry….

Dose a great job for cleaning out an engine that has carbon build up problems. Helps with fuel economy a lot also.

Put this in my 2016 Honda Pilot Touring and it seemed to make my Pilot run smoother. It could be a Plasibo effect but I never got the same feeling when using another brand Seafoam.

Use all your products for my car

Use 1 bottle in all our 5 vehicles 2 times a year and have noticed slightly better mileage and drivability. Great product at a very reasonable price.

So important to use before an oil change. Especially for the GMs that are direct injected. Treat yourself don’t cheat yourself.

I added this to my stock style radiator for my classic muscle car. It lowered the coolant temperature dramatically in the heat of the Florida sun in the summer. I would run at 210° now I barely make it to 190 on average I’m hovering right at my thermostat which is 185. The car runs amazingly well

I have to admit I've tried a lot of fully synthetic oil but AMS oil is second to none I highly recommend it you can feel the difference you can feel the power for my 2007 Chevy Silverado 1500 classic