Awful MPG?

[alexd3498]

Hello everyone, a few months ago I got a legacy touring XT. Loving it so far, but lately I've been getting horrific mpgs. I don't drive it aggressively, so this has been a bit concerning. Also, the cvt NEVER LISTENS! If I floor it it rarely ever goes, and if I roll into the throttle it accelerates like crazy. Anyone else noticing this on theirs? Thank you!

 

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[whitexc]

Sounds like a trip to the dealer with your concerns. Thats pretty bad mpg. Heck I could load your car into the bed of my truck and get that lol.

 

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[Yoda_One]

Colder climate? Fully warm engine/CVT before pushing the vehicle? Winter gas? Driving on hilly roads? Heavy acceleration?

 

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[alexd3498]

Colder climate? Fully warm engine/CVT before pushing the vehicle? Winter gas? Driving on hilly roads? Heavy acceleration?

 

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50s to 70s, always warm up my engine before pushing it, I don't gun it like crazy because I hate the cvt lol no point in flooring it if it never listens anyway

 

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[laufu]

Hi Alexd3498

 

Your mileage seems low. Do you encounter a lot of stop and go traffic? Are you disabling the Auto-Stop Start?

 

Regarding the throttle behavior. That is normal and how Subaru programs their throttle for their automatic (old) and current CVT transmissions. It behaved like that on my previous and current Subarus. (4 Legacies, an Impreza, a Tribeca and an Ascent).

[gathermewool]

I agree that you should be taking your car to the dealer.

 

I disagree that the described throttle behavior is normal. Subarus are known to be touchy with an exaggerated throttle curve, but they do NOT bog then, after letting up on the throttle, accelerate like crazy. That makes no sense! Sounds like a possible Throttle position sensor or even a CVT issue.

 

Two points re: your MPG:

 

1. The wording of your posts leads me to believe that you weren't always getting such bad gas mileage. So, what's changed, if anything (e.g., commute change to all city, lots of idling time/warming your car for extended periods of time before driving off, etc.)

 

2. What kind of change are we talking about? 15 --> 12? 25 --> 12? Big difference there and a major data point we're missing to make any sort or recommendation.

 

3. What are you seeing for boost during the strange throttle response behavior? Are you seeing full boost while at the lower than expected RPM that remains after you let off the throttle, with its resultant increase in RPM, or is it truly bogging down initially?

[alexd3498]

I agree that you should be taking your car to the dealer.

 

I disagree that the described throttle behavior is normal. Subarus are known to be touchy with an exaggerated throttle curve, but they do NOT bog then, after letting up on the throttle, accelerate like crazy. That makes no sense! Sounds like a possible Throttle position sensor or even a CVT issue.

 

Two points re: your MPG:

 

1. The wording of your posts leads me to believe that you weren't always getting such bad gas mileage. So, what's changed, if anything (e.g., commute change to all city, lots of idling time/warming your car for extended periods of time before driving off, etc.)

 

2. What kind of change are we talking about? 15 --> 12? 25 --> 12? Big difference there and a major data point we're missing to make any sort or recommendation.

 

3. What are you seeing for boost during the strange throttle response behavior? Are you seeing full boost while at the lower than expected RPM that remains after you let off the throttle, with its resultant increase in RPM, or is it truly bogging down initially?

 

1. Not much has changed, though I did schedule an appointment to the dealer! 2. It started with still not the best average mpg of around 19, but it's gradually dropped in mpg in the past few weeks, finally reaching the 12's these past two fillups.

 

3. Boost has been very unstable, many cases it's been full boost with low throttle, and no boost with high throttle, definitely a bizarre disconnection there. I've had it where I accelerated to get onto the highway and it feels as slow as my 2017 2.5 legacy, and other times where im going 25mph and the thing wants to pounce! Also, I've definitely has this bogging issue, where nothing happens when my foot is down, but when I let go of the gas, it's up to high rpm's and holds the revs for a few seconds

 

Will let you know how it all goes after my appointment!

 

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Edited November 18, 2021 by alexd3498

[caddygti16v]

Have you tried to re calibrate your throttle?

 

Here is a link, doesn't take long and is worth a shot.

 

https://www.subaruoutback.org/index.php?posts/6045751

 

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[gathermewool]

Dealer. Something something warranty

[2wookies]

Dealer. Something something warranty

 

Lol exactly

[hkshooter]

I agree with others, take to dealer with concerns.

 

And yes, the throttle is typical Subaru CVT response. I've owned five CVT Subarus from 2016 and up and all of them have done this. It's especially noticeable with the 3.6 and XT models. Mat the throttle and it's a dog out of the hole. But if you give it say, 2/3 throttle, then once it gets rolling mat the throttle, the acceleration is greatly increased vs just flooring it and holding it there.

I've said it for years, Subaru's first priority in tuning and throttle response is "protect the CVT". They purposely limit torque from a standing start to save slippage and abuse on the CVT then as the car gets rolling they allow power increase to max available, all to protect the CVT.

This is my seat-of-the-pants feeling when driving, not proved by Subaru documentation. Anyone paying an ounce of attention to the car should be able to feel this and duplicate it.

[MoleMan]

I would not trust the MPG readout at all. I generally fill up the car use the tank then calculate by hand. But surprisingly the Subarus are fairly accurate to about a half a gallon and not off by a few MPGs like other cars.

 

But under 13 MPG is pretty bad. If I recall this was an issue when the Ascent came out as well with a lot of complaints of sub 20s MPGs. I am thinking a possible oil change and verify that it’s synthetic may be the answer. But agrees with others bring it back to the dealership but they will probably say it’s normal etc... if the problem persists keep bringing it in.

 

And about the CVT Subarus CVT really likes slow take offs. It really sucks when you try to go like in a merge situation and the car won’t move. But then again I bought my 3.6 just to coast and drive slow. I have other cars for fast fun. It’s still loads better then the Nissan CVT however which is more like a broken vacuum cleaner.

 

Just a funny comparative my 2006 3/4 ton Dodge Diesel with a controller and exhaust does not even get 13 MPG pulling a 27 foot toy hauler through the mountains.

Edited November 23, 2021 by MoleMan

[alexd3498]

Took it to the dealer and they did two software updates, and subaru is making me fill up 4 fillups at the same gas pump, measure mpg and mileage, and send them the receipts.

 

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[bms231]

interested in seeing the outcome of this

[alexd3498]

Nothing new on the mpg issues, but this has been happening while driving as well as a black infotainment screen, eyesight gone too

 

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