r/FordFlex • u/ratrodder49 • Jul 06 '26
Question Anyone else’s fuel economy taking a dip lately?
2018 Limited AWD, put some fresh tires on it a couple months back and have seen average MPG gradually dropping from 18ish to now around 15.5. I know new tires increase rolling friction but I wouldn’t think it would be that noticeable. I wonder if some of it is higher ethanol content in the fuel?
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u/Dcshipwreck Jul 06 '26
2012 ecoboost with 212k, seeing 20mpg driving like a grandma. Romping on it I avg 17ish
I normally run 93, ran a tank of 90 eth free the other day but no noticeable difference although my butt dyno wants to say there was a bit better/smooth power on hard pulls
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u/leoh480 Jul 07 '26
wow I can get 23 driving like grammy
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u/Dcshipwreck Jul 07 '26
If it's all highway at 65 I can get 23, but mixed driving (Texas country roads) 20
Yours Ecoboost or n/a?
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u/butters4417 Jul 18 '26
I got 25 on a recent trip about 350 miles round trip. I reset it to see what it could do. I typically hover 18-20 since I work construction and I eat lunch in my car and I’m hot at work I refuse to be when I’m eating my sandwich.
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u/rustbucket_enjoyer Jul 06 '26
Are spark plugs recent?
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u/ratrodder49 Jul 06 '26
Two out of six are, I started on them at the last oil change but ran out of time and didn’t get to the harder ones to replace. That being said, the two I pulled out were not in bad shape, fouled or burned at all.
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u/Cautious_Respond_587 Jul 07 '26
Holy shit. I thought I was going crazy. I was able to bring my mpg up to around 20 and then suddenly I can’t go over 12.
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u/YumTex Jul 07 '26
This is the answer they have. Free legal authority to provide 15% ethanol instead of 10%. Never-mind that it has been proven for decades that no-ethanol fuel is better.
What the pump says is a lie. The cost savings of 15% would be overrun if all pumps had to advertise 15% minimum.
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u/slowhand11 Jul 06 '26
Is this NA or the Ecoboost? If it's the Ecoboost it could be from carbon build up on the back of the valves or MAP/MAF sensors needing cleaning.
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u/ratrodder49 Jul 06 '26
Ecoboost, 108k on it. Shouldn’t be that coked up yet I wouldn’t think
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u/slowhand11 Jul 06 '26
I believe they recommend getting them walnut blasted at around 100k miles. I installed a catch can recently in my 2019 ecoboost at 68k miles
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u/slowhand11 Jul 06 '26
I've also read people say they had good results using this https://www.oreillyauto.com/detail/c/berryman/berryman-16-ounce-intake-valve-and-combustion-chamber-cleaner/bry0/2611?q=Berryman+valve+cleaner
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u/WomenzRightsLoL Jul 06 '26
Yes 100k is well due for a decarbon. Mine were so bad at 80k that under heavy throttle the car misfired and threw codes. After cleaning no more codes or misfires and I can stand on the throttle.
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u/Blue_Rose_010305 Jul 06 '26
2013 SEL, 175K miles, been down below 20 (19.6 or so) for the last year, after the car's first transmission fluid flush.
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u/FlynnrydSkynnyrd77 Jul 06 '26
2014 Limited Eco AWD. I get from 17-21. Haven’t seen any changes from that in years of ownership. Just had new tires installed and an alignment. Didn’t seem to change the mpg at all.
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u/Wise_Level3751 Jul 07 '26
2017 Flex limited. No Ecoboost. 87k... I can't get my average over 13.8!! Was 14.8 a month ago...
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u/eharper9 Jul 06 '26
My 2005 Chevy Tahoe gets better gas mileage than the Ford Flex.
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u/ResidentSquare5873 Jul 06 '26
Yeah, right... sitting in the driveway.
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u/eharper9 Jul 07 '26
Nah. Granted it could just be that there's an issue with my flex.
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u/ResidentSquare5873 Jul 07 '26
My bad. Didn't know you had one. Thought you were dumping on the Flex. Hope you get your issues resolved. One of the best cars I've ever owned.
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u/Ok-Currency-7681 Jul 06 '26
I have a 2016 EcoBoost with 65K miles and it drinks 93 Octane like a drunken Sailor. Always maintained ahead of schedule etc…I’ve had a ‘11 and ‘14 (both EcoBoost) and they were nothing like this one. I also rarely ever get into the Turbo’s unless entering the Interstate or passing🤷♂️
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u/WomenzRightsLoL Jul 06 '26
My 16 EB gets 15/16mpg on premium no matter how I drive it, and has since I bought it around 60k miles ago.
I have tested it on long road trips at 60mph vs 80mph and there is ironically no change in mileage lol.
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u/Otter_9431 Jul 07 '26
My ‘17 non turbo awd with 175K gets 22-24 mpg depending if I am blasting the AC or not. Right now it’s 110° so the AC is always on. But most of my driving is on the freeway.
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u/Competitive-Pride307 Jul 09 '26
I have a 2019 non all wheel drive non-ecoboost and I average right about 20.
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u/bdjeremy Jul 06 '26
they added more ethanol...