Since its summer - The AC is going on for many - I used mine all day 2 days in a row and logged about 350 miles -- It seems I sacrificed 32 mpg ( AWD 2023 ) 2.5 NA - down to 29 MPG - I just rotated the tires and oil change - So thats about 10% loss in mileage mainly at freeway speeds 70-80 mph -- Anyone else have A/C stats on their CX5 when in heavy use ?

 

Tire pressure has a great influence when you are using the AC.
Check the tire psi early in the morning and before the sun hits the tires or the ambient temperature starts to raise.

AC places a load on the engine so during the summer of frequently using the AC it is better to spend the extra $$ and use only the highest octane fuel.
The misconception regarding this octant use goes back to not understanding how the ECU regulates the engine operations.
The common sense for MPH is the best MPG with or with out AC use is to lower your speeds to at least a max of 65 mph.

Simple math will conclude the question do you really need to get to your average destination 10-15 minutes sooner? Leave sooner get better MPG and a safer journey!!!

The little things that make some positive supporting improved MPG when using your AC.
Clean engine air filter
Clean cabin filter
Spark plugs with less then 30k miles use
Rinse off the condenser at least at the start of summer and use of the AC system.


The reduction using AC of between 3-5 MPG is perfectly normal.
The strongest influence to that number is how you drive when using your AC and NOT so much anything else. This is why that number can vary so greatly when you ask what others get.

 

Funny enough even with utilizing all the horsepower and torque on my car and having the AC on full blast when it's really hot, the gas mileage will go down but still stays respectable lmao. That's something I really love about these cars, they are consistent. My previous 2013 Acura RDX would often get like 18-20 MPG if you used the AC/Heat on full blast while driving in the city, but it was always random.

 

Yup it’s a great engine

 

For me, the biggest thing I find that affects my gas mileage is how many traffic lights I have to stop at.

At lights . . . I'm getting 0 MPG (infinte liters per 100 KM.) LOL.

And also if I take short drives (to pick up the kids) because I let the engine warm up before I take off. (Again 0 MPG). So for short drives, the warm up is a bigger percentage of my drive.

So, trips on the highway I'm getting as low as 8.58 L/100KM.

Trips around town stopping at stop lights I'm getting about 9.71 L/100KM.

If I take the backroads through town and the round-abouts, my CX5 says I'm getting 9.1 L/100KM.

This, so far, is all with AC. We just got our CX5 3 months ago.

Take care.

 

on a fully gas run engine no one gets ZERO MPG. Its only that your display like most all vehicle is programed not to show you what you are actually getting while idling.
The drive-by-wire is adjusted to be at about 11-12% that means the throttle is not completely closed when idling so you are still using fuel.
The main reason many get poor MPG in city driving is their direct use of the throttle. Without knowing they just use to much throttle to get to the speeds they want.
At one time auto manufactures included a vacuum gauge but so many owners thought it was more of a HOT ROD novelty instead of using it as a means to gain improved MPG.
If anyone hooks up a simple service vacuum gauge, they can see that you do in fact pull Hg at idle, so you are using fuel.

 

If you're idling and not going anywhere, you're getting ZERO MPG.

 

@Callisto

For that gauge . . . does that max out if you stomp on the gas. But if you lightly press on the gas to get up to speed it doesn't max out?

If so, I was just thinking about that the other day. LOL. One of my buddies had that on his car. He had sported up his Volkswagen Rabbit way back when.

He was constantly maxing out. Stomping on the gas.

I'll stomp on it if I need to make a lane change after the lights. But I've gotten more into just taking my time to get up to speed.

When gas got expensive . . . I turned getting better gas mileage into a game. LOL. I also track gas mileage with the CARFAX app on my phone.

I'm getting better gas mileage than our 1st gen Rogue. Of course our Rogue is old. And I'm sure I need a wheel alignment on it. LOL. But our CX5 is getting better gas mileage with a roof rack + carrier basket up top. So I'm a happy camper.

 

LOL
auh ya................ that's often a false assumption from forum members when this subject comes up and I post what I did .. You like so many are using the wording and not the actual volume used while idling. LOL
Mabe next time look at the pictures i posted.
You are obviously NOT in the automotive service world and basically have never used an ODBII or CANbus ECU/PCM diagnostic scanner.
So for those that understand let me try a different way to explain it...

ABC of idling fuel consumptions simplified:
Platforms and gas supplied engine used may have very different % never the less it can be stated gas consumption while idling can average .07 gal(or more) or this can be included in the term MPG if the time idling is added up in an hour idling period.

BTW one of those 2 gauges installed by OE clearly show this at ide represented in ECONOMY or what you are misunderstand that term for technical value MPG.
I suggest you look up the basic steady Hg of a gas run engine and yes your MAZDA at idle is. Clue... It isn't zero.. lol


Gasoline engine idle at between 14-19Hg.

 

Yes it will bury the gauge or in the case of a Turbocharged or Supercharged engine that is when you go into boost levels .On only quality digital pressure/vacuum equipment can you read the small amount of vacuum at WOT levels.

Jun 21, 2025 | 09:19 AM