On July 7 of 2016, independent lab testing from AAA, North America’s largest motoring and leisure travel organization, finally put the old debate of whether running no-name gasoline damages engines or not to rest. Cheap fuel has officially been exposed for what it really is: an engine destroyer. For years we have been told that all the big-brand gasoline stands in America offer the same schwill as the unheard-of corner stores, and that occasionally adding a tank of premium to a Camry won’t help a damn thing. But testing has now proved otherwise, as a 34-page docket by AAA reports that “among brands tested, non-TOP TIER gasolines caused 19 times [emphasis ours] more engine deposits than TOP TIER brands after just 4,000 miles of simulated driving.”

According to the study, having enhanced, engine-cleaning detergent additives apparently does make a huge difference, as they prevent carbon deposits from negating fuel economy, lower emissions, and positively impact vehicle performance in newer vehicles. AAA urges drivers to use a gasoline that meets TOP TIER standards for optimum engine cleanliness and performance, as John Nielsen, AAA’s managing director of Automotive Engineering and Repair revealed that, “As advertised, tested TOP TIER gasolines kept engines remarkably cleaner than other fuels we tested.”

Since 1996, the EPA has mandated that a minimum level of detergents be in all gasoline grades sold within the United States in order to lower engine carbon deposits, which is when the TOP TIER program and performance standards first came into play. But many gasoline companies and automakers felt that even stricter guidelines needed to be put in place, a fact that proved somewhat fruitless, as two-thirds of all U.S. drivers believe there’s a difference in the grade of gasoline sold by different gas stations, but still value convenience and price over quality.

“Americans are six times more likely to choose a gas station based on the price of gasoline rather than the quality of the fuel,” continued Nielsen, making drivers sound even more out of touch by explaining that, “TOP TIER gasoline is widely available and only an average of three cents more per gallon.”

To ensure a gas station sells a high quality petroleum, consumers should always research the fuel options near them and avoid cheap alternatives, and with one-third of all gas stations meeting TOP TIER standards for fuel quality, reversing previous fueling mistakes is easier than ever. “Consumers can reverse some engine deposits simply by switching gasoline brands,” says Greg Brannon, AAA’s director of Automotive Engineering. “After a few thousand miles with TOP TIER gasoline, performance issues like rough idling or hesitation during acceleration can often be resolved.”

Back at the lab, it’s worth noting that this wasn’t just some overnight operation either, but a full-blown investigation. For testing, AAA first took both TOP TIER and non-TOP TIER gasolines from a southern Texas market since it accurately represents the kind of fuel sold in most areas of the United States. Premium fuel (93 octane) was then chosen as the grade of choice for the evaluation due primarily to the tendency for some brands to put a slightly higher concentration of detergent in this grade of fuel, thus leveling the playing field for petroleum suppliers by forcing them to bring their best to the table.

AAA then hired the services of an independent certified engine testing lab (International Standards Organization 17025) to perform what is called an ASTM International standard test on all of the fuels. This lab often performs this sort of test hundreds of times over the course of a year for fuel companies and automotive manufacturers, and has been widely accredited for its professional and effective testing methods.

Prior to testing, the Ford 2.3L port fuel injected engine — which has been the standard industry test mule for over 15 years now — had its cylinder head cleaned, critical clearances measured, and fresh intake valves installed. The engine was then alternately pumped full of cheap and TOP TIER fuels and operated at speeds that would be encountered during highway driving continuously for 100 hours, thus simulating 4,000 miles of real-world driving.

After each session was completed on a certain kind of gas, the engine was torn down for inspection, and once the cylinder head was removed, components were visually inspected and weighed by an ASTM certified rating professional to identify the level of deposits. All components were then photographed to show the build-up of carbon deposits for comparison and public forewarning purposes. By documenting its findings within the exact same engine, and using back-to-back testing on both cheap and TOP TIER fuels to minimize variability, AAA was able to successfully measure intake valve and combustion chamber deposits left behind by various gasolines. Results proved that even premium grades of cheap gas hurt more than help.

After looking at all of these findings, we reached out to automotive expert and Product Training Director Richard Reina over at CARiD.com. Reina tells us that after perusing the 34-page report, he can confidently attest that this isn’t just some conspiracy to get Americans to pay more at the pump, but a legitimate reason to spend the extra few cents a gallon in order to protect your vehicle and the environment.

But according to Reina, Americans still have this “bottom feeder mindset,” where saving a few bucks on a fill-up is the only way to go even though most drivers admit that TOP TIER gas is more than likely better for their cars. People should know that opting for cheap fuel could spell expensive maintenance fixes down the line, especially on modern motors, Reina warns, and compares filling up on the low-grade stuff to getting full on Wonder Bread and Peter Pan peanut butter. You’ll have a full belly, but there is little nourishment there, and the long-term negative effects of opting for junk every time are scary.

Reina also stresses that the modern day automobile engine, with all of its turbocharged and supercharged ingenuity, requires better gas than older designs. This is due primarily to the fact that fuel atomization/injector spray patterns can be negatively affected by cheap fuel, and their advanced compression ratios and sensors are far too sensitive to be put at risk by using low grade gas.

When asked what his take was on the future of fuel regulations, Reina says that it will likely be a long time before the EPA forces refineries to up the amount of detergents in their gasolines. But he also notes that if those aforementioned engine sensitivities cause warranty claims and widespread customer complaints, automakers will likely begin putting recommendation decals on gas caps much like they have with motor oils. If things get bad enough, Reina believes that a large push from automakers could force the hand of the EPA, and in the process eliminate low-grade gas once and for all in America.

But until that day comes, the best advice we can give you is don’t buy cheap gas, dump in a high quality fuel cleaner if TOP TIER is not available, and run a high-grade tank of 93 Octane through every now and then, even if your car doesn’t call for premium. Companies like Shell will often save its strongest detergents for these grades, and running it through your fuel system will help clean out a lot of the gunk left behind from cheap gas. For anyone who is curious as to which companies made the list of TOP TIER gasoline retailers, current rankings can be found here, and for further reading here is the full report on AAA’s findings.