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Mazda CX-7

I was wanting to know if I do need to use premium gas in the Mazda CX-7. I have been told I can use regular and the engine would compensate. I have also been told not to use it that it would ruin the engine. Before I make this purchase I want to be sure of what I am getting into.

You need to find out what the manual says. This is a turbo 4, which often requires premium. It also get v6 level of mpgs.

Texases is correct. Ask to see the Owner’s Manual for this car, and for any other car that you are considering. Rather than relying on what you “have been told”, you need to see the vehicle manufacturer’s statement on this issue. In addition to the manual, many vehicles have a concise statement on or near the gas filler cap regarding the grade of fuel.

The key point to remember is the difference between “premium fuel recommended” and “premium fuel required”. I won’t insult your intelligence by explaining the differences in meaning, but I do want to point out that even on vehicles where the word “recommended” is used in regard to premium fuel, while the vehicle will run satisfactorily on regular grade gas, there may be a noticeable reduction in both engine power and in mpg.

That is the case with my car, a Subaru with the H-6 3.0 engine. The engine starts and runs just fine on regular gas, but if the “recommended” premium gas is not used, the normally very fast acceleration is somewhat slower and my gas mileage drops by 1-2 mpg.

According to some folks over at mcx7.com, there is some kinda re-flash for the older CX-7s that will allow it to use regular and that the newer ones should be able to use regular just fine. However, one produced a graph from their onboard diagnostic unit that showed they got worse fuel mileage, power, and performance from using regular. Some even reported bucking and jerking from regular as well.
If you are afraid of having to fill up with high octane fuel, the CX-7 is NOT for you.

http://www.mcx7.com/showthread.php?t=1731
Owner’s manuals. file size ranges from 6 to 10MB, so beware when downloading it.