ok i have a 2005 RX-8 with les then 27,000 miles i just got the car and the first week i went trough a tank in 3 days (145 miles 9.5 gallons 93 oct.) the next tank i went through a tank in another 3 days (154 miles 10.1 gallons 93 oct.) this weekend i drove around town stop and go traffic but nothing major i went 67.23 miles and uses 6.98 gallons 93 oct. for a total of 9.6318051 mpg. what can i do. the car has a fresh oil change not even 500 miles on the oil change new air filter. what can i do what should i do please someone help.

 

Sorry but engines will use more gasoline to stay idle (or slow traffic) than moving traffic. Rotary engine, due to its poor heat transfer efficiency, it needs even MORE gas to stay @ idle.

Highway miles is on par with piston engines, however.

9 mpg ... hmm ... thats a bit too low, how fast u drive? 5 mph ?

but u can always replace plugs and coils (if u havent do so) to see if it increase any of the mpg, also check CAT.

 

check/replace the plugs, plug wires and cois, at 45k miles I was getting only about 160 miles to a tank, where before I had no problem pulling 200, after I replaced everything my mileage went back to over 200 per tank, right now im ast 215 with a little under 1/4 of a tank left all city driving. and i premix too

 

Replace hell i just got the car less then 2 weeks ago. i was told by a friend to have the comp flashed will this do anything? what do u mean PREMIX?

 

That's too low. First thing to do is verify all the recalls have been done on it and you've gotten the latest flash. Log into Mazdausa.com and put in your VIN. It should note if if you have any recalls that haven't been performed.

If you have the lastest flash then I'd try resetting your fuel trim to allow the car to adjust. With the car off disconnect the negative terminal to your battery then with it disconnected step and hold the brake down for a few seconds. Reconnect the battery and start it up. Then take it on a normal drive. Be careful because it will be relearning the idle trim so it's possible it will stall out at stops.

See if that improves it. If it doesn't then there's a few other reasons for it to be occurring and I'm sure people will add in possible causes/fixes here but at some point you should go to the dealer. It should be warrantied until next year. Do you have any history on the car? Was it certified pre-owned? All that info would help.

 

Take it to the dealer.

 

You're getting half the mileage I get. There is something seriously wrong with your car.

Did you purchase from a private party or a dealership? The seller needs to own up to the problem with your car.

Edit: Actually I calculated out your first 2 tanks to be around 15mpg. This is bad, but normal if you are beating the hell out of the car, staying in high revs, all short trips. The 9mpg tank is a bit low but can be accounted for if you are making extremely short trips.

I think you need to lay off the throttle. Either that, or there is something seriously wrong with your car.

 

this was a dealer car. i bought it with 26,2xx miles on it. also got the ex bumper to bumper

 

HAAHAHAHAHAHAHH! LMFAO!!!!!!!!! dude u must be drivin the **** outta ur car....try keeping your shifts under 4k and try downshifting and braking...u use more gas throwin it into neutral and braking, than downshifting and coming to a stop

 

downshifting is why you have a manual lol

 

NO im not driving the **** out of it.. BTW its a 4 speed AUTO down shifting is done for you.

 

What does having just bought the car have anything to do with it? Most dealers will not replace plugs and coils just for the hell of it just to turn around and sell the car used. It's an '05 with 26k, I can tell you this having been extremely close to the ways of a dealership service department...a used car inspection goes something like this. Is there any major damage to the vehicle? Y/N Does the vehicle run/idle normal? Y/N Is the state inspection current? Y/N

They do the bare minimum to get the vehicle out on the lot for sale. Sorry but you got screwed. Take it to a reputable Mazda dealer and have diagnosed.

And for the record, our race cars average 8-10 mpg's at full race speeds! You really need to have your plugs and coils looked at.

 

Hey man, I have an 05 Auto..(34000 miles)for the past three weeks I suddenly saw my gas milage drop down from about 16 to 9. Now my cars sitting in the dealership with a seized/blown engine and im waiting on the replacement to come in. Techs have no idea why it blew. Just a heads up, look into it, its a problem

 

I have an idea...and I'm sure others have the same idea I do...AUTOMATIC!!!

 

im noticing very slow acceleration. my friend has an automatic non turbo no super charger or anything all stock and can sit at a stop light and punch the gas and spin the tires. mine wont even barely go. when you go whats is the acceleration like?

and no automatics should get better then 9 or 10. also looked and the mazdausa says nothing about any needed recalls

 

I realize you just bought the car but at 27,000 miles, you need to start looking into some routine maintenance.

- spark plugs
- wires
- ignition coils
- Air Filter (dirty ? clogged?)
- Run some fuel cleaner through the tank

Your first two tanks of gas come out to 15.26 mpg and 15.25 mpg. That last tank is pretty miserable though at 9.63 mpg.

 

You live in Dallas?!

Why don't you go to one of the car meets in Dallas? I'm sure someone has an automatic that you can either ride with them, or they ride with you to tell you if your car has the right performance it should.

I've gotten as low as 7mpg in my car, but that was at a practice day for autocross. Literally less than a 100 miles on a full tank of gas. My tires haven't been the same since.


Last resort is go to the REGIONAL FORUMS and ask about a good dealer to take your car to. Try to get a compression test for free, but if all else fails PAY FOR ONE. If the car is as low in power as you say it is you probably have low compression.

 

I can attest to the fact that this car is TERRIBLE in the city. I have QUITE a few 10-12mpg experiences. It's terrible. However pure highway (say something like 90/10) will net you MPG in the late teens.

 

The longer you idle, the worse your overall mileage. At a standing-still idle, ALL engines get zero mpg.

9mpg is an indicator of a problem. Have your engine checked by someone who knows what they are doing. Also make sure your gas tank didn't get drilled.

 

ok just for clarification this was not traffic stop and go it was normal city driving stop for a read light then go not like sitting in rush hour

 

ok.4 sp Auto transmisson car. that explains it all.

Check your motor. You might be really low on compression.

 

Do you have a link to do this? I can't find anywhere, where I am supposed to enter the VIN.

 

^^ under owners, register to the site with your VIN

 

I'd say, you're basically screwed. Why?

1) It's an auto.
2) It's an auto.
3) 15.26mpg, then 15.25 mpg isn't that bad considering (sorry to say this again) it's an auto, and you're just driving around in the city, rather than cruising down the interstate say, on a nice long trip.
4) the last mileage you should'nt really count as true. The variable fill up amount of different gas pumps with only 7 gal of fuel isn't going to get you an accurate mileage. If you average your three fills up you get ~13.8 mpg which isn't great, but then an auto RX-8 isn't an economy car.

As to what are you going to do, I'd say try a few of the ideas above to make sure all mechanical items are up to snuff for mileage...and if it doesn't help...sell it if the buying the gas gets you down.

 

In an RX8? Check the street for an oil spill.