I just got an '04 GT and I am wanting to know if I really need to use only premium fuel. Will it hurt the engine to use a lower grade? What fuel number types are the best, like 91 or higher? Also, I know the oil should only be non-synthetic oil, which should be mineral oil, but I dont kow which exact kind I should use.

 

ok stop.
read your last thread.

 

consult your owner's manual.
If you don't have one, register under the owner's section of www.mazdausa.com for fuel and oil recommendations.

My personal opinion: use only 91 octane, this motor has been known to not be happy with lower octane fuel at high rpm's.
As for the oil: either follow the owner's manual or consider something different given your location. (ie; hotter climate owners usually run 'thicker' oil)

This has been discussed hundreds of times of the years so I encourage you to familiarize yourself with our forum's search feature.
Congrats on the '04.

 

^agreed!! this has been answered thousands of times....

I always feel..higher octane= more timing advance=move "cylinder" pressure=more power....I always use 93 oct and castrol gtx 5w30 oil with 8-10 oz premix each fill up

 

damn jedi I used to b a post ***** just as much as you (well almost) now i feel as if I'm well behind your high post count haha

 

Not one of these again. Search darn it.