Increases fuel mileage
351309
I use this additive on all my engines, the mileage stays high, the engines operate smoother and my plugs last longer
4936982
It had been about 50k miles and was time to replace the filter I had been using that came w/ my intake. I had been using a outerwears filter sock which helped tremendously. This new filter improved MPGs and was easy to install.
3280276
As always i add this product to my cars and truck for performance, no this isn't the large power gains that their cold air intake provides but you will notice a difference, and not sure they say you get better mileage but mine has gone up with all cars and a truck that i own. More air flow why wouldn't you want your car or truck to breathe better?
3771632
I initially used Royal Purple's other (older) fuel system cleaner and didn't notice any changes. As such, I was skeptical when I poured this stuff into my tank. However, my skepticism was unfounded because my fuel economy gradually began increasing. After I was done with this tank of gas, my fuel economy was up almost 5 mpg. This new formulation really works.
4289072
Only reason for 4 stars - once the fuel needle valve's rubber touches fuel, it expands quite a bit.  Make sure you put these in fuel before setting your float height as it will change a lot.  Had to pull carbs and reset float height on both.
978955
I have a 2012 6.7 liter diesel Ford. This stuff really did make a difference and their fuel additive did as well. I went from 14 miles a gallon to about 16 and a half using both. I was quite impressed and I won't drive my $60,000 vehicle anymore without using their product. It runs and sounds different. If you try it you'll know what I'm talking about
2989050
I own a 1999 Subaru Forester and add Lucas 10013 Fuel Treatment almost every time I fill up. The engine runs noticeably smoother with improved gas mileage. My car runs better on non-ethanol gas but it's not always easy to find it. The Lucas treatment eliminates the negative effects of ethanol gas. I highly recommend it. Definitely buy this 1-gallon sizeit's much more economical than buying individual small bottles.
1000045
I did not compare fuel mileage.  However, this really catches a lot of the CCV by-product.  Super easy installation, easy maintenance, and it works.
1028680
Installed on my 2003 Ford Expedition 5.4L without issue. No real MPG increase, but the manual calls for the fuel filter to be changed every 30k. Nothing wrong with having cleaner fuel running through the motor.
1033825
I seem to notice a slight increase in acceleration and gas mileage.  Time will tell if they will really last the lifetime of the car.
3977648
this arlen ness big sucker made a huge improvement on my FLHX in hwy performane and increased my fuel mileage. should of had one when they first hit the market.
3691799
My car has a better pickup, now that I am using the AEM Dryflow Air Filter and the gas mileage has improved, but i have not done enough driving to see how much the gas mileage has improved. I am going to drive about two (2) thousand miles in the near future and will be able to tell how much it has improved after that trip.
3019985
This did seem to improve airflow and will reduce maintenance cost over time but the surprise to me was that I noticed an increase in gas mileage, to the tune of 2-4 miles per gallon.  Installation was a breeze and it may be my imagination but my bike felt a little more powerful off the start.
3739276
My engine had been running smoothly enough before I put this in the gas tank, but when you're used to smooth enough, you forget what a treat *really* smooth is. And my engine runs *really* smooth now. Even better, this product delivered on its promise to improve mileage: I added it to the tank two fill-ups ago, and over the course of those two fill-ups I'm about 4 mpg better than I was in the previous two fill-ups.  (And driving conditions have been pretty similar across that period: roughly the same mix of highway and local roads, equivalent use of accessories, etc.) I know that boost isn't going to last forever, but I'm grateful to have found a product that delivers. I will add 16 oz of this stuff to my tank every couple thousand miles as recommended.
1139742
Allows more air intake, where you can take foot off and vehicle cruises further for better fuel use,
and vehicle accelerates better than with OEM.
977918
After I did a full tune up on my car, I ordered two of these and I have to tell you that my gas mileage is way better than before. 4.5 city to 5 gallons extra highway.
181122
Cleaned up the injectors, now I have better gas mileage