I laugh. I have a membership with BJs Club (similar to Sam's) and buy their gas that is typically a dime cheaper. After studying various gas brands, BJ's fuel is among the worst you can buy (minimum detergent content). LOL. My '93, 5.2L, Dodge truck eats it up. Engines weren't so picky back in the day.

 

Dude there is NO Costco hate only that the fact about their fuel is not accurate. But mentioning that word does tend to rally others around the thought. Lot of that going on these days off forums.
For someone that keeps up on the service of their vehicles and takes care of them you question some information and use less than the best fuel for them? lol
You wouldn't notice a difference because you don't use or have any monitoring equipment except your "Butt" dyno and what the MPG indictors is. And even that is suspect?
Your vary statement "drives the same with all gas" is evidence that you are not as much a car enthusiast as you have given all of use long time members the impression about yourself on this forum?

I have given the tools to aide in anyone to test their Mazda when using different brand gas and octane values and it's easy enough for anyone to do? well maybe not you from your response?

 

That decade they were very sensitive to gas values. The emission system just starting to become better than the 80's but gas types and octane used cause all sorts of internal engine issues. Most were usually not necessarily noticed at first.......
Ever wonder why and what caused the engine oil to turn dark so fast?

 

honestly asking about what gas to use on any forum always goes the same way.... there are so many that make claims with not real facts to back them up, diehard product users and are blind to any real information and the owner of a car that states they use anything for gas and never had a problem or noticed one brand from another and lastly most all the unwellness to experiment and use some form of equipment to verify claims made or to just learn something new.
No one or the rare person who wants the best for their vehcle will really will change what they are using for fuel and I hope they don't .....
I view most of those as future service customers.... LOL $$$$$$ for me

 

Cut her a break, Castillo. We all have our opinions, informed or not. But we all can apply a weight to each person's opinions. She gave her opinion based on her experience. As for me, when I want to know something automotive related I hit YouTube, forums, and watch videos only from mechanics and engineers and never rely on only one opinion. I'll watch many videos on one topic and get as close to consensus as I can. That's how I ended up with a Mazda. The close-to-consensus was Mazda was right up there with Honda and Toyota quality without the brand image upcharge. I still believe that is true.

 

I change oil every 3K or 1 year whichever came first...often the 1-year came up first. In fact, my next 1-year comes up next month. I'll have only about 1,600 miles since the last oil change.

 

WOW! My compliments on your rare to read servicing!!!

 

Being retired makes this possible.

 

This thread is like what oil is best for beating a dead horse.

THE FACTS:
Normal gasoline:
The EPA regulates the minimum number of additives of gasoline, and they must comply with the minimum amount
a) Pentane content. Minimum 95 volume percent. (b) Benzene content. Maximum 0.03 volume percent. (c) Sulfur content. Maximum 10 ppm. (d) Chemical composition. Be composed solely of carbon, hydrogen, oxygen, nitrogen, and sulfur.
Aside from the minimum requirement all else is proprietary. We no idea what else is in it.


Top Tier Gasoline: Aside from the above the only regulation is it must include increased levels of detergent additives compared to normal gasoline.
What and how much more and exact levels of each or proprietary. We have no idea.

In other words, except for the minimum EPA requirements, no one except the gasoline manufacturer really knows what is in their product.
You can use various tools to measure the effects, but you still have no idea what it is you are actually putting in your tank.
Like most products, it is based on consumer opinion and what they can afford.

So how about we start another tire thread...that should go well...

 

The tire threads go the same way....