Climate effect performance???
 

First time user of this forum so first I apologize if I am opening this thread in the wrong place. I recently purchased a 2004 RX-8 with the Grand Touring package with 30K this past summer. I was getting between 17 - 19 mpg on a tank and 70% of my driving is hwy. Now during the Texas winter I have seen a considerable drop in my performance to 14 - 15 mpg.

The car now has 40K miles and I believe I have done the proper maintenance and care for the rotary engine. My guess now would be perhaps the climate has something to do with the performance. Is this true??

This fall the gasoline in the DFW area went to a new methanol blend for at least the winter. I noticed my mileage drop, but not as drastically as yours.

You have 40k on your car, have your plugs been changed yet? My mileage dropped significantly around 32k. Plugs were changed for a TSB and my mileage increased back to normal immediately. If you havent had your plugs changed yet you may want to consider it.

do a tune up, it's only air filter and spark plugs, and see if it help, also try different gas station.

I don't live in Texas but I have a similar issues. It seems directly related to our oxygenated winter gas blend that is mandated (at least here) starting November 1 until at least the of February (and I hope no longer). My mileage had been 22-23 consistently and after the gas switch it dropped. I've been getting 19-20 now, with a random fluke 21 sneaking in there. I have a little under 11K now, so my case is not mileage related.

Thanks for the input, I'll check on the plugs and repalce the filter and see if I see any changes in performance.

Dense.....
 

In addition to crappy ethanol/gas mix, the cold has a definite effect - the MAF sees really colder denser air coming in and adds more gas to compensate. Like they say, the rotary loves the cold!

You may be able to feel the extra power (I do, but my air here is usually at -10*F or better!) but your mileage can really suffer if you "stretch it's legs"!

S