Alright, so I took my car in for the 9k oil change and told them my CEL has been on and off a couple times over the past month. I asked them to up the ECU to the newest code level (which I don't see any evidence of ) and when I went to pick it up the mech. asked me what fuel I used. I told him super, and he said "that's why your CEL is coming on, you're running the plugs too hot, the car was designed for regular - use that."

OK...now the manual says super, most people on here are using super...sooooooooooooooo that sounds fishy.

Anyway...anyone have any suggestions...I'm going to have to go back and complain that they didn't flash it, so I might as well have some ammo for arguing his fuel statement if it is indeed incorrect.

 

tell him to RTFM, they want to make excuses so they don't have to figure anything out.
The gas door says premium recommended, open it next time he says so. Then ask him which part of the car that he designed since he is such an authority on it. I have only put 93 in mine with the exception of once when all the premium pumps were "out of order" then I only put a couple of gallons in. Never had a CEL.

 

You probably know as well as me, but I've never heard of anyone, anywhere, with any car getting a warning light for using a higher grade gas. I put midgrade in my old Accord, just because it gets better mileage, even though the manual says to use regular. And since the manual even says super, I don't know why this guy would try to put that by you. Maybe he's too lazy to do a proper diagnostic. Doesn't the car store the CEL codes whenever the light goes on? My bet is that there's no code for "Gasoline is of too high a grade", but you could check the listing for it. All I have to say is that that sounds stupid. I'm glad you're going back to complain.

 

I've actually had the local VW dealer tell me the same thing after I took my Passat in for CEL. Turns out it had misfire codes. Dealer told me they had been having some troubles with misfires lately and their might be a load of Premium gas with some troubles, so run regular for awhile. Turns out he was right...once I got through that tankful of Premium (CEL came back on several times) and ran regular for a couple of tankful's I switched back to Premium and have never had a problem (that was a couple of years ago)

 

Typical dealer "technician" BS.

However, I have recently switched to 91 (from 93) and have seen an increase in performance and mileage.
Probably for the reasons I've outlined elsewhere, but I am still monitoring for knock as the weather gets warmer.

 

Y'know, when I was doing some research into my car options, I was putting the RX-8 up against the Acura RSX Type-S and the Pontiac GTO (I love purple, and a purple car with purple leather and purple gauges was exceedingly tempting )... and I noticed on Edmund's comparison pages that the RX-8 was listed as taking "regular unleaded" while the other two took "premium unleaded". I actually really shocked to see in the user manual that it was recommending 91 octane (premium) fuel...

Now, I realize the manual is the manual, and it's straight from Mazda, but Edmund's has "regular" and the guy's mechanic said "regular", and that really makes me wonder.

I had kinda put aside the craptacular mileage because I had hoped/thought that I could pull it off with regular. I don't race, I don't burn rubber, I just wanted a car with a little oomph and good handling (and style to die for ), so now I'm wondering about this... In the San Francisco Bay Area, the difference between regular and premium is 30 cents a gallon in many of my local stations (running theme seems to be about 20 cents up from regular for midgrade, another dime up from that for premium...) I suppose the extra $20 a month in gas isn't going to kill me, but hey, that's my monthly NetFlix subscription!

What grade of gas is everyone running? (Maybe this should be a poll? )

...Paul

 

I run 87 regular and have been for 6 months; my car runs great and I get 19+ mpg. I live in Southern California where the temps get blazing hot, and running with the A/C on constantly, the car runs like a champ.

 

I don't know about lighting up your CEL light, but a good argument can actually be made to support your mechanic's statement that you'd be better off running 87 octane gas. It looks like the rotary actually may prefer the cheaper stuff.

Check out https://www.rx8club.com/showthread.p...ghlight=octane

and https://www.rx8club.com/showthread.p...ghlight=octane