Customer Ratings & Reviews

I had tried many different brands of fuel system cleaners, and none ever had particularly good results. For a while, Chevron Techtron was about the best that one could buy, until the advent of AMSOIL P.I. Performance Improver. The AMSOIL version was the very first in giving a noticeable improvement at once. "At once" like when leaving the gas pump. I've been buying AMSOIL P.I. Performance Improver for years now. And whenever I buy a used car, the first thing I do is add two bottles of AMSOIL P.I. Performance Improver and fill it up with Shell V-Power gasoline. That's a truly great combination to clean out a neglected fuel system. I also use it every couple of thousand miles in my cars for maintenance. I buy it by the case and keep it on hand for my use and if someone else runs into a fuel issue. The only thing that I don't like about it has been the change to the red bottle. YUK! I liked the former bottle much-much better, both in appearance and in being able to see the actual product through the clear bottle.

Gained mpg after one use.

Been using this for several years. My Ram loves it!

can tell a difference after using P i Performance Improver Gas Additive I will be using it again

I hooked up scan tool and STFT and LTFT was 12.8% and 6.9%. (short term fuel trim and long term fuel trim) After using this 0% that's a perfect stoichiometric ratio. For just riding in town. I would suggest if you cannot drive 30 min on highway to put vehicle in sport mode a couple of uses. Great product

Using this product will prevent excessive carbon build up in the chambers and piston tops.

Excellent fuel cleaner, had a friend on a Honda civic that had a catalytic converter code.. after two treatments of this fuel additive cat code disappeared and has not come back on most shops probably wouldn’t replace the catalytic converter for efficiency. Even said his gas mileage is better. Highly recommend this additive for your fuel system!!

Hard to determine improvement as with most if not all addatives

I've never had any fluel injectors problems in using this product for 20 years and at least 8 cars.

I have a Huge Tundra 2008 with 37" tires and my gas mileage is bad--So I started to use this P.I. and my mileage started out at 9.9 mpg---after using P.I.--now it's up to 11.2 and I'm always trying things to help this motor-- So I would say it works

I have a 02 Dakota that never got good gas mileage it would always very one week I’d get 8-12 mpg currently getting 14 -17mpg Might also helped that I replaced my transmission but either way noticed an improvement using the Pi.

Use as directed keeps injectors clean

Noticed no difference

I had a 2003 Ford Focus that got 25mpg going back & forth to work. With the fuel tank just overt ½ full I put a full bottle of P.I. in the tank and ran it to almost totally empty. After that the car got 31- 32 mpg back & forth the 35 miles round trip to work. The P.I. cleaned out the fuel system and the car was more fuel efficient afterwords!

Have been using this product in all my gas powered vehicle for years. Have never had any starting or mileage issues. No indication of valve problems. Highly recommend.

Works very well and improves gas millage

Most the time I carry one bottle in my car when I'm on road trips. I like to put it in on the last tank of gas before I get home. Not sure if it does anything but my car does seem to run alittle smoother. Normally I just run ethanol free gas and never use fuel additives.

Great product. More powerful acceleration; quieter operation; reduced knock from heat and cheap or old fuel.

I add Amsoil P.I. Performance Improver Gasoline Additive to all my vehicles every 3 - 4 months. Since I have done this I have had absolutely no problems with injectors and valves. I have to assume it is working, but in any case it provides me a sense of reassurance that I'm doing some preemptive maintenance. Thank you Amsoil for providing top notch products!

We trust this product to keep the valves clean on an eco boost engine.