[bonchef]

I have a 2007 Mazda 3 and mileage was on the decline couple of years ago. At some point my engine light came on from time to time and found to be a temperature sensor (? not sure where) issue. After $200 fix at Sears my mileage was back to normal. Recently my mileage is actually rising beyond when it was new (at 200K km now). My garage uses Kendall brand oil.

Btw, the above was my only fix for this car ever. Just bought a '16 6 today and hope this one will be as reliable... finger crossed - you never know these days with global supply chain and all that factor into the equation.

 

[Mjk1009]

I don't know about you guys but lately I have seen an even further drop in MPG. I'm seeing 24.8 average now. My driving has not changed and I'm about 80% city 20% hwy...I have no idea wtf is causing my drop in MPG. I've driven my '14 for about 22k now and I've never seen it average more than 28mpg...and now it's 24.8.

 

[Donkey Grundle]

I don't know about you guys but lately I have seen an even further drop in MPG. I'm seeing 24.8 average now. My driving has not changed and I'm about 80% city 20% hwy...I have no idea wtf is causing my drop in MPG. I've driven my '14 for about 22k now and I've never seen it average more than 28mpg...and now it's 24.8.

Have you checked the air filter? I'm only at 13k and noticed that the engine back, especially near the intake, was already filthy.

 

[Mjk1009]

Have you checked the air filter? I'm only at 13k and noticed that the engine back, especially near the intake, was already filthy.

Yep I changed it out at 20k. Anything else I should be looking out for? I've checked my tires and those are good as well.

 

[dp741]

Yep I changed it out at 20k. Anything else I should be looking out for? I've checked my tires and those are good as well.

UPDATE: 1-30-2017
I put on new front rotors and brakes. No more judder, drives perfectly smooth. But very little increase in gas mileage. No longer think this is the issue. Perhaps I just started driving more aggressively as I got more comfortable with the car? Either way I see 42 on the current MPG when driving 65-70mph on flat ground, but I average 26mpg driving 80mph everywhere and some city 30/60 split.

-----------

Out of curiosity Mjk1009, do you have the brake judder issue as well? Where sometimes your steering wheel shakes from braking application?

I noticed right around the same time my car developed this judder, my gas mileage dropped by ~1/3 (35mpg->25). I am going to replace the rotors soon or have my old ones machined with an on the hub lathe and I am betting this will result in a large mpg increase.

My understanding of the judder issue is that for some reason the rotors are not perfectly square with the pads (hub tolerance, rotor warping, whatever the issue). As a result, the rotors rub slightly and buildup pad material on them which causes an ever light "drag" that is not noticeable when the dealer checks for a dragging caliper. However this drag is enough to cause a judder in braking and lower mpg.

 

[iTour6]

Is it just the front rotors that go bad or is it all four that cause the judder?

 

[Horn17]

I've never been able to achieve the mid 30's average MPG's that a lot of members consistently achieve, nor have I expected to. I think most that get those mid 30's have the i-eloop technology which already puts me a couple MPG's behind the eight ball.


I probably drive a close to 50/50 average city/hwy driving over the course of a tank which gives me another "-" in the MPG game. Add in the fact that getting top MPG reading never really has been an important to aspect me. If I can still average in the 27-29 MPG range while maintaining my driving style (which I'm the first to admit is the opposite of being conducive to high MPG's) I still feel like I'm coming out ahead of the game.

 

[dp741]

Is it just the front rotors that go bad or is it all four that cause the judder?

not sure, but pepboys and other places will resurface all 4 while mounted to the hub (what mazda TSB mandates, but no dealers seem to perform) for $160. I have been debating between doing this and getting aftermarket rotors

 

[draken]

I've been in the upper 30s to low 40s in MPG. Single occupant and mostly highway commuter miles help a lot, as does a light foot.

 

[Finite_Precision]

I've had 20-21 mpg for the last 3.5 years of Mazda 6 ownership. Never saw more then 34 on freeway and only under "lab conditions"

 

[dp741]

UPDATE: 1-30-2017
I put on new front rotors and brakes. No more judder, drives perfectly smooth. But very little increase in gas mileage. No longer think this is the issue. Perhaps I just started driving more aggressively as I got more comfortable with the car?

Either way I see 38 or so on the current MPG when driving 65-70mph on flat ground, but I average 26mpg driving 80mph everywhere and some city 30/60 split.

I guess it is still impressive that I can average 28.5 on a 200 mile roadtrip going 85mph most of the way, but I was expecting a little better for a car with i-eLoop that was rated at 42mpg on the highway.

 

[Mason Dixon]

Whats best way to calculate mpg?

 

[rabbit]

I bought my used CPO 2014 Mazda 6 in March of this year. I was excited to experience the great fuel economy I had been reading about when I had been researching cars prior to the purchase.
I've had roughly 2.5 Fuel ups. Avg mpg is 26 at it's best. I do about 20%Hwy/80%City. Not sure why it's this crappy. And from alot of people who have posted 30+ numbers, can you confirm that your 6 doesn't have the i-Eloop tech?

I don't know if anyone else has noticed this, but the fuel tank capacity is 16.4 gallons. I barely get 15 gallons in at fill ups, which I usually do when there's about 5miles left to empty. It would be assumed that 1 gallon is left for reserved....but when I'm filling up, pump stops at 14.5 gal. I squeeze in an extra 0.5 forcefully, which I know I shouldn't, but that's just me testing if it's actually the pump that's bad. I've tried 3 different gas stations with the same result. I am unable to physically put in 16.4 Gallons!

All-in-all, I like the car, it's a good drive, but the mpg is disappointing. I am going to keep tracking it through the first few summer months, suspect I'll be filling up roughly 4 times in the next couple months so let's see how it goes.

 

[rabbit]

Whats best way to calculate mpg?

What I've been doing in the past is going by how many gallons I put in at fill up and how many miles I drive since that point on. So reset your trip A or B at your next fill up. Record the gallons put in or save the receipt. And then when you stop to refuel again, just quickly divide the miles driven by the gallons put in last time, this will give you an average mpg (hwy and city combined).

hope this helps, and hopefully you can post back with your recorded mpg! I'm curious to know.

 

[GWL]

I bought my used CPO 2014 Mazda 6 in March of this year. I was excited to experience the great fuel economy I had been reading about when I had been researching cars prior to the purchase.
I've had roughly 2.5 Fuel ups. Avg mpg is 26 at it's best. I do about 20%Hwy/80%City. Not sure why it's this crappy. And from alot of people who have posted 30+ numbers, can you confirm that your 6 doesn't have the i-Eloop tech?

I don't know if anyone else has noticed this, but the fuel tank capacity is 16.4 gallons. I barely get 15 gallons in at fill ups, which I usually do when there's about 5miles left to empty. It would be assumed that 1 gallon is left for reserved....but when I'm filling up, pump stops at 14.5 gal. I squeeze in an extra 0.5 forcefully, which I know I shouldn't, but that's just me testing if it's actually the pump that's bad. I've tried 3 different gas stations with the same result. I am unable to physically put in 16.4 Gallons!

All-in-all, I like the car, it's a good drive, but the mpg is disappointing. I am going to keep tracking it through the first few summer months, suspect I'll be filling up roughly 4 times in the next couple months so let's see how it goes.

Not crappy as city mileage is rated 26 mpg and you drive 80% city, can't expect it to be much better unless you have 30+ miles of driving each way to work.
Those people who are getting 30+mpg are driving more highway.

 

[nobouncecap]

A few things i have done is cleaned out the MAF every few months AND add seafoam. However, the way i use sesfoam is through the brake booster tube while the car is on. The tube will actually suck up the seafoam and stall out. I let the engine set and then start the engine up amd white smoke comes out.

 

[DJP2016]

:

Whats best way to calculate mpg?

:wink2: Did you skip 6th grade math????

 

[Jerrycobra]

I bought my used CPO 2014 Mazda 6 in March of this year. I was excited to experience the great fuel economy I had been reading about when I had been researching cars prior to the purchase.
I've had roughly 2.5 Fuel ups. Avg mpg is 26 at it's best. I do about 20%Hwy/80%City. Not sure why it's this crappy. And from alot of people who have posted 30+ numbers, can you confirm that your 6 doesn't have the i-Eloop tech?

I don't know if anyone else has noticed this, but the fuel tank capacity is 16.4 gallons. I barely get 15 gallons in at fill ups, which I usually do when there's about 5miles left to empty. It would be assumed that 1 gallon is left for reserved....but when I'm filling up, pump stops at 14.5 gal. I squeeze in an extra 0.5 forcefully, which I know I shouldn't, but that's just me testing if it's actually the pump that's bad. I've tried 3 different gas stations with the same result. I am unable to physically put in 16.4 Gallons!

All-in-all, I like the car, it's a good drive, but the mpg is disappointing. I am going to keep tracking it through the first few summer months, suspect I'll be filling up roughly 4 times in the next couple months so let's see how it goes.

I can tell you this engine is thirsty in city driving. I do almost 100% city driving quite often in Los Angeles and 24MPG is the most I muster. this engine does not like stoplight to stoplight traffic. On the contrary for long highway drives 36MPG is petty common for me. I have a OVT tuned engine but MPG didn't change much for me.

 

[snowflakezoom14]

After owning my GT for over two years now my mileage is pretty predictable depending on the driving conditions. I only have a 2.5 mile commute to work and that with my local driving I will range from 24 to 26 mpg. If I manage a little highway driving in the mix I will see up to 28 mpg. Just got back from a road trip to Florida. Most of the time I was averaging about 36 mpg, with a couple of segments 38 mpg and better. That was with two passengers and a trunk full of luggage. Speed between 70 to 75 most of the time. Did a sprint from Tampa to Miami with 4 passengers, full trunk+, speed 75 to 80 and mpg was around 30 mpg. I love the cruise control, but mpg wise I did a better job when I was controlling the gas.