Gas Guzzler

[Huascar82]

So I just filled my tank up today and after calculating mpg, it came out to 13.5 mpg. WHAT THE HELL I GOING ON????? usually I get around 17-18mpg. I do a lot o city driving with short 10-15 minute trips, and I havent done more then normal since my last fill up, I normally shift either a 3k or a little below 3k RPM. Using 93 octane gas and non synthetic oil ( get it changed a Faulkner Mazda and they insist mazda recommend non synthetic). Am I doing something wrong? should I be doing something? oh and the car only has 14k miles. OH and I've had to start letting the car warm up for about 5 minutes cause of the damn cold. Actually thats another question, I remember my father always saying that you should let the car warm up, even in the summer, but I really dont see many people warming up cars anymore. Should it still be done?

Any ideas are appreciated.

 

[gooniac33]

So I just filled my tank up today and after calculating mpg, it came out to 13.5 mpg. WHAT THE HELL I GOING ON????? usually I get around 17-18mpg. I do a lot o city driving with short 10-15 minute trips, and I havent done more then normal since my last fill up, I normally shift either a 3k or a little below 3k RPM. Using 93 octane gas and non synthetic oil ( get it changed a Faulkner Mazda and they insist mazda recommend non synthetic). Am I doing something wrong? should I be doing something? oh and the car only has 14k miles. OH and I've had to start letting the car warm up for about 5 minutes cause of the damn cold. Actually thats another question, I remember my father always saying that you should let the car warm up, even in the summer, but I really dont see many people warming up cars anymore. Should it still be done?

Any ideas are appreciated.

your car uses a gas while just sitting. And city driving is some of the worse for the mileage. However I get no less than 19 with mine when I do city driving. It is more like 25-27 on the highway at normal speeds meaning 65-70. My car does have almost 32k miles on it though. You may want to take it in and get the recalls handled. Mine is driving way better since I got it back and the mileage is a little better too.....

 

[orng1]

Damn that's got to suck. It would ALMOST have made more sence to have gotten an SUV... But I can't stand "trucks" for daily driving. Yeah MPG will be affected by the idling. There isn't too much need to lket it idlke for long, just long enough foroil to circulate through the head. Cars are way different from when you NEEDED to let it idle. I can't imagine it'd be too different with the weather, maybe better.

 

[Igve2shtz]

The cold weather is horrible for gas mileage for multiple reasons:

Cold air is denser, meaning for proper air/fuel ratio (as determined by the ECU) will need more fuel for proper combustion.

While the engine is cold, the ECU will run in "open loop" mode until it reaches proper operating temperature which wastes gas because it takes longer to reach that temperature.

Doing quick drives of less than 15 miles is also horrible because the engine never reaches operating temperature, and thus every time you turn ont he car, the engine takes longer to warm up.

Letting the car idle to warm up wastes alot of gas but it is HIGHLY RECOMMENDED, especially for turbocharged vehicles. While it would take about 15 minutes at idle for the car to reach proper operating temp, and that is a long amount of time, until you reach that temperature, you should refrain from any quick accelerating and you should keep the boost low. You need the oil to warm up to make sure you have the proper oil pressure in the bearings or else bad things happen.

To put it in perspective: I live about 40 miles directly East of Philly, so I experience the same temperatures you do. In the summer time, I averaged 24 mpg. Last week, I averaged 20 mpg, all things being the same - I drove the same roads, with the same mods, no excess weight, and I even have been trying to drive more conservatively.

 

[chriscecc914]

get an ems and have the car tuned. More power and they will lean it out safely for better fuel mileage.

 

[Sacrilicious]

you definitely do not need to warm your car up for 5 min by idling it. what you should do instead is to simply let it idle for 20-30sec so that the oil pump can get the oil circulated throughout the engine and then drive the car gently until the engine warms itself up. drive it around while being gentle with the throttle and it will warm up naturally. idling it for a long period of time just lets water vapor build up in your exhaust, which is going to promote rusting.

another important thing to note is that if you warm a car up by idling it, even though the engine temp is ok, the transmission is still ice cold, so you're only getting half of your drivetrain raised up to operating temp. that's not a good thing...=/

 

[Sacrilicious]

as far as your gas guzzler problems, i'm going to bet that it's just a combination of the colder weather and your 5 min warm up. i mean, you figure if you do many 10-15min trips that require a 5 min warm up each, then you're wasting a good amount of fuel each trip just warming your engine up. hell, that means you spend 33%-50% of your trip idling! (eek2)