2010 Mazda 5 Really bad gas mileage

[jason10phan]

Help guys , i do not know what wrong? Mods, Intake and lowered) . On a full tank of gas i am getting only 325 to 350km, half tank about 190 to 200km and the other half 125 to 150km. To me i am blaming on the car being lowered. before i lowered it , i would get around 400km to 450 km . . Please help.

[ReD~DrAgOn]

Change your air filter if its dirty.

and a lighter right foot!

But ultimately, How much gas do you fill your tank with to how far you're driving?

[tonyzoomzoom]

Here's a few things to consider (which have been discussed before):
- after lowering, did you do an alignment on your car?
- winter gas gives lower mileage than summer gas (antifreeze, etc)
- most gasoline now have ethanol = lower mileage than before

[jason10phan]

Brand new SRI, always use 91 or 94 octane chevron, and i try not to drive past 4000 rpm ( okay i lie , sometime i go faster ). To fill my tank it cost me around $ 35 to $55 ,and the car was alignment at Dale's alignment. . Should i take the car in to see if there is anything wrong? It seems to be getting worst after when it was lowered  in the summer time? 4 month now i have been driving under 3000 rpm, and still it has not improve.

[tonyzoomzoom]

you should read up on some of "bad mileage" post in the general mazda3 discussion.  A lot, if not all of that, would apply to the Mazda5.  there is also some advice to how to properly calculate fuel consumption (not mileage per tank).

btw, Chevron has ethanol in all its gasoline grades.

[jason10phan]

Okay so ur saying that even it say no ethanol 0n 94 oct, but it still does?. Yes i read a lot of that already , no help there.( Mazda 3 forum) Thank anyway. Come to how many km per tank, i am very good at that, like i say, i will keep u guys up to date what i get every week.

[DKaz]

Completely fill your tank, reset the trip meter to 0, drive normally, fill up again, tell us how many km and how many litres you filled up.

In the winter I use about at least a litre more per 100km.

Is your car standard or auto? If standard, don't go more than 3,000rpm. If auto, don't mash the gas pedal in. Slowing down the acceleration will help a lot. Check tire pressure. Consider using lower weight oil, 0W20 is a good winter oil unless you like to push your car, then stick with 5W20. And like Tony said get your wheels aligned. Is your car broken in yet?

[Tim25]

btw, Chevron has ethanol in all its gasoline grades.

Nope, no ethanol in Chevron 94!  

Also know when your AC compressor is running... any time you are running the windshield defrost, defrost with foot heat & foot heat alone (IIRC) runs the AC compressor. 
Read up on how to properly calculate your mileage.  "Half a tank" etc. is not a proper measurement.  You need to know how  many litres it took you to go the distance.

     TIM

[tonyzoomzoom]

thanks for the correction on Chev 94

[ReD~DrAgOn]

Damn I love it with defrost and foot heater So I should just have it on the forward vents to help save gas?

[disqx]

Brand new SRI, always use 91 or 94 octane chevron, and i try not to drive past 4000 rpm ( okay i lie , sometime i go faster ). To fill my tank it cost me around $ 35 to $55 ,and the car was alignment at Dale's alignment. . Should i take the car in to see if there is anything wrong? It seems to be getting worst after when it was lowered  in the summer time? 4 month now i have been driving under 3000 rpm, and still it has not improve.

Why are you using 91 or 94 when 87 is recommended?

[DKaz]

No only defrost and defrost with foot heat will have A/C come on. All the other three modes will not do it. But I have automatic climate control all the time and I don't notice any significant decrease in fuel economy.

[Golddragoner]

Completely fill your tank, reset the trip meter to 0, drive normally, fill up again, tell us how many km and how many litres you filled up.

In the winter I use about at least a litre more per 100km.

Is your car standard or auto? If standard, don't go more than 3,000rpm. If auto, don't mash the gas pedal in. Slowing down the acceleration will help a lot. Check tire pressure. Consider using lower weight oil, 0W20 is a good winter oil unless you like to push your car, then stick with 5W20. And like Tony said get your wheels aligned. Is your car broken in yet?

Haha, but that takes all the fun out of it. I almost never stay below 3000rpm...people beside me must love it when I downshift with a rev match to 4500rpm

[DKaz]

I love double clutch rev matching.

[Tim25]

You are also throwing away money by using 91 or 94 octane.  Your 5 is new and tuned to run on 87, use it.

Because ignition timing and compression are not optimized to run the higher octane fuel, in theory you could get worse fuel economy with the higher grate gas.

     TIM

[jason10phan]

Okay thanks, this sunday i have to fill it again. Right now i am at half tank. I see 205 km only, i will fill my tank from now on with 87 octane to see if there is any different. Okay Tim25 i will put 87 for a month to see if there is any change. Right now my car has 17500 km.

[zoomerboomer]

Just record your odometer reading on your gas slip each time you fill; then you have the actual numbers in order to do the math.  Next time you fill, just subtract the previous reading from the current reading and calculate the liters /100 kilometers that you used since the previous fill.  As Tim25 would say, it isn't rocket science!  See this thread.
http://www.bcmazda3.com/forum/index.php/topic,21155.0.html