Royal Purple 11754 Max-Clean Fuel Cleaner - 6 oz.

This is the best. It will stop most 'old engine' problems. Its not going to magically repair anything that ails your engine, but for engines with some years on them, engines with knocking issues, poor acceleration, or seriously depressed mpg this product is one of my top 3. I use this one just once every year or so, or after I've been particularly demanding on my engine, especially out places where i know fuel quality might not be up to spec. I'm looking at you Death Valley. This is really the product i recommend for fixing and cleaning out engines. I once passed a smog test by running two of these through a tank. (Not recommended...) For more routine use I use techron additive. I truly believe in preventative maintenance when it comes to my car; and this coupled with routine oil changes, using quality gas, letting your car warm for just a minute or so, and keeping good tire pressure is one of the best things you can do to extend the life of your engine and get the best mpg and performance possible.

My truck was running rough. I put off doing any maintenance till the check engine light came on saying some knock sensor error, telling me the little tough truck needed some loving. So I put a new set of spark plugs, wire set, distributor and fuel filter. And finally added this to clean the fuel system. Now the truck is running great as ever. I've reset the check engine light and it hasn't yet come on. And I can feel the difference. The problem with issues like this is that the performance falls so gradually over time that, a regular person cannot notice the difference. But, after the maintenance the change was quite easily felt - Smooth idle, quick start (in freezing cold in MN) and improved peppiness when stepping on the gas. One thing I've noticed is that the car exhaust smokes a little bit when running after adding the additive till it has burned through the system. Maybe burning off the soot and grime. Then it smooths out. Since it is a product or Royal Purple I am hoping they know what they are making. And I'd buy it again when the time comes.

I haven't used it yet to comment on its effectiveness but I was surprised at how small the bottle is - however, it is my own fault, as it's published in the description. For the money, I thought I was getting a more "traditional" sized container (e.g., Seafoam and Techron are 16oz and I think I was looking at the 20oz Max Clean and accidently selected the 6 oz). Keep in mind, a Coke can is 12 oz, so this is half the size. As a public service announcement, get the 20 oz as it's the much better deal. The 6 oz, at$1.60 per oz, is literally 2x the cost.

I don't notice any real difference in the performance or gas mileage but use it as part of my normal maintenance with the oil changes (this, RP oil filter and RP HMX oil) to keep things running fine.

this is my first time using this product and it seems to work better then the other products that i have used. it seems to really quite down the engine and make it idle just right so it doesn't jump around.