I think top tier recognized that their minimum was not enough for modern engines. Still leaking info, but this is what they say, I guess we can assume more additives. Anyhow, put the gov't in charge and it will become a bad joke. It's a si-1 commercial the top tier website. The EPA screwed it all up by having insufficient additive levels for modern engines. Take the EPA out of it and report your additive levels, the consumer can handle the info. The top tier was set by port injected engines that wash their valves naturally, and don't explode if you have a little carbon build up. To manu's credit they are driving change, they are course correcting, but a lil late there buddy.
The website
toptiergas.com is operated and managed by the
Center for Quality Assurance (CQA), on behalf of the automotive manufacturers who sponsor the
TOP TIER™ Program. [
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The program and its performance standards were originally created in
2004 by leading automakers (including BMW, General Motors, Toyota, and Honda). It is now sponsored by a larger group of manufacturers to ensure fuel quality meets the demands of modern engines, often exceeding basic EPA detergent requirements. [
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Would you like help locating
TOP TIER™ approved fuel stations near you, or do you need more information on how the TOP TIER Detergent Gasoline standard compares to standard TOP TIER Gasoline fuels?
Use our Station Finder tool online or get the app to locate TOP TIER™ approved stations near you.
Fuel retailers are starting to roll out
TOP TIER+ fuels in late 2025. By January 2027, most (if not all) approved brands should have transitioned for gasoline.
Diesel fuels will have both the Base and Plus options available depending on the station.
As for "my" Costco...
Yes. Costco is an officially certified
TOP TIER™ and
TOP TIER+ gasoline retailer. Both their regular and premium Kirkland Signature™ fuels contain five times the EPA detergent requirement, ensuring optimal performance and cleanliness for your engine.
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