Gas mileage tuneup. Give me things to do!!

[Mike2000z28]

Alright well i have posted before about my serious gas mileage issue noone can fix or figure out. Basically getting around 7mpg in the Winter and around 10mpg in the summer. Car was scanned, nothing, has around 80k miles. No noises lights, etc or smells. I have a very light foot, but it is pure city stop and and go driving. It is a 2008 cx9 GT. Fuel filter, plugs/air filter? What else am i missing? Mechanic says fuel injector cleaning, but im not sold on that. It really is catastrophic mileage and for a car guy very frustrating for a truck to get Top Fuel mileage even Hummer H2s are probably getting better than me at this point.

Give me some ideas!

Mike

 

[xxxmonoxidechil]

At 80K id say a fuel filter and everything tune up related would be a good idea anyways. Otherwise id be looking at emissions related equipment like the O2 sensors and Cat's. As any of those not working correctly can really screw up the air/fuel ration and get it pretty wonky.

 

[IslandTractor]

That is truly horrific gas mileage. If the dealer cannot find anything, I'd want the regional Mazda technical rep to review matters. You mileage is WAY out of bounds.

 

[Capt.Blackadder]

No error codes and you're still getting the mileage of a WWII Sherman tank? I would change the spark plugs, air filter, and motor oil, and then proceed to give it an Italian Tune-Up. Find an empty stretch of road with no cops around and just absolutely bury your foot in that throttle from stand-still all the way up to the speed limit on that road (or beyond, if you dare). Freeway on-ramps with traffic metering work well for this purpose. You said that you basically only use it for city stop-and-go driving? If that's been going on for a long time, perhaps all that it needs is to clear its throat, so to speak, with 10-20 full throttle romps like that. Even better, take it to a tune-up shop with a dyno and let them run it for a good while at full throttle. That method takes the cops out of the equation.

This Italian Tune-Up method has worked like a charm with my vehicles through the years. They always pass emissions testing with flying colors and they deliver the claimed mileage from their manufacturers. Good luck!