2024 Maverick Hybrid drastic drop in MPG after 32,000 miles

[casraipfang]

2024 Maverick Hybrid. Bought it in Feb 2024 48,500 miles. No engine mods or anything that would affect mileage was done until April of 2025, when I added Ladder rack. HV battery replaced in April 2025 at 35,000 miles by Dealer. Live in mountainous area of San Diego CA.

Conditions: Constants.

1. Normal Drive Mode all times
2. AC in Auto set to 70° all times.
3. Drive 35 miles one way to work, and 35 miles back, same route every day since purchase.
4. Same 2 gas stations used to get gas.
5. Factory tires (225/65/17) were replaced at 16,000 miles (they were inflated to 45 psi), replacement tires (235/60/17) were wider and inflated to 35 psi. ( I am on my third set of tires).
6. Windows up at all times.
7. Cruise control on and set to 70 mph 80% of the time while on highway.
8. Engine air filter replaced at regular intervals, and the cabin air filter was replaced at 40,000 miles.
9. Oil changes done at every 5,000-7,000 miles Full synthetic Mobil one. Performed by the same place every time.
10. Bottom engine cover was removed at 10,000 miles to minimize cost of oil change (so it was off well before the drop in mileage).
    

Conditions: before issue HV battery started to fail

1. On my way to work (2 steep downhill mountain roads plus in town and highway): getting 45-49 mpg
2. On my way to Home (Highway and in town, followed by two 2 steep mountain roads): getting 29-30 mpg
3. on average I would get 34 mpg an about 450 miles to the tank. Verified by manually filling and calculating miles driven. (This matched the on board calculation as well.)

Conditions After HV battery began to fail and after it was replaced.

1. On my way to work (2 steep downhill mountain roads plus in town and highway): getting 32-36 mpg
2. On my way to Home (Highway and in town, followed by two 2 steep mountain roads): getting 22-24 mpg
3. on average I would get 27 mpg an about 365 miles to the tank. Verified by manually filling and calculating miles driven. (This matched the on board calculation as well.)
4. It was a slow decline from 34 avg mpg at about 32,000 miles, then the HV battery began sending error code. after about a month (couldn't get to the dealer at the time), it dropped to 27 avg mpg and stayed there. HV Battery was replaced and the mileage has yet to return to normal.

Things I plan to do:

1. When I have to get new tires, will get the factory size again.
2. Remove ladder rack ( even though I was getting 27 mpg before it was installed).
3. Have alignment checked
4. Pull spark plugs and inspect
5. Check injectors for clogging
6. Check calipers to see if one or more are stuck

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[Techcar]

I hope when they did the work that they also did a complete relearn for the ECM.

 

[zweber21]

Battery replacement at 35k seems odd. Why did it need to be replaced?

 

[Escapologist]

Well, I'd say something in the charging went fucky, as it seems to be in the vein of "keep swapping downstream O2 sensors trying to fix a bad cat" kinda thing.

 

[Maverick123]

Put your hand near the wheels after a long drive, if you have a stuck caliper that corner will be super hot compared to the others

 

[identifyasatruck]

copy that zweber...i am also curious on what Ford said when they replaced the battery at 35k. on a different thread (re:charge cycles)...i just got through commenting to The Real Maverick that i was cool with abusing my battery with the L button.

 

[LSchicago]

Been a hot year.

 

[pigsareus]

2024 Maverick Hybrid. Bought it in Feb 2024 48,500 miles. No engine mods or anything that would affect mileage was done until April of 2025, when I added Ladder rack. HV battery replaced in April 2025 at 35,000 miles by Dealer. Live in mountainous area of San Diego CA.

Conditions: Constants.

1. Normal Drive Mode all times
2. AC in Auto set to 70° all times.
3. Drive 35 miles one way to work, and 35 miles back, same route every day since purchase.
4. Same 2 gas stations used to get gas.
5. Factory tires (225/65/17) were replaced at 16,000 miles (they were inflated to 45 psi), replacement tires (235/60/17) were wider and inflated to 35 psi. ( I am on my third set of tires).
6. Windows up at all times.
7. Cruise control on and set to 70 mph 80% of the time while on highway.
8. Engine air filter replaced at regular intervals, and the cabin air filter was replaced at 40,000 miles.
9. Oil changes done at every 5,000-7,000 miles Full synthetic Mobil one. Performed by the same place every time.
10. Bottom engine cover was removed at 10,000 miles to minimize cost of oil change (so it was off well before the drop in mileage).

Conditions: before issue HV battery started to fail

1. On my way to work (2 steep downhill mountain roads plus in town and highway): getting 45-49 mpg
2. On my way to Home (Highway and in town, followed by two 2 steep mountain roads): getting 29-30 mpg
3. on average I would get 34 mpg an about 450 miles to the tank. Verified by manually filling and calculating miles driven. (This matched the on board calculation as well.)

Conditions After HV battery began to fail and after it was replaced.

1. On my way to work (2 steep downhill mountain roads plus in town and highway): getting 32-36 mpg
2. On my way to Home (Highway and in town, followed by two 2 steep mountain roads): getting 22-24 mpg
3. on average I would get 27 mpg an about 365 miles to the tank. Verified by manually filling and calculating miles driven. (This matched the on board calculation as well.)
4. It was a slow decline from 34 avg mpg at about 32,000 miles, then the HV battery began sending error code. after about a month (couldn't get to the dealer at the time), it dropped to 27 avg mpg and stayed there. HV Battery was replaced and the mileage has yet to return to normal.

Things I plan to do:

1. When I have to get new tires, will get the factory size again.
2. Remove ladder rack ( even though I was getting 27 mpg before it was installed).
3. Have alignment checked
4. Pull spark plugs and inspect
5. Check injectors for clogging
6. Check calipers to see if one or more are stuck

Put your hand near the wheels after a long drive, if you have a stuck caliper that corner will be super hot compared to the others

yep - put hand near - not ON wheel.

 

[Edge Haley]

Someone on this site 2-3 yrs ago in a 2022 Hybrid had the same problem. His final conclusion was his upgrading to a wider tire contributed to more wind and the wider tires were 2 or 3 pounds heavier on each tire....his brother who owned a large tire store replaced his tires back to original OEM size, tread and weight tire and MPG went back to original MPG. He and his brother were both surprised at the results.

I've consistently got 42.5 to 43.0 mpg since day one Jan 14.2022 still on original Continental tires. Vehicle manufacturers are under federal government pressure to provide maximum MPG...so they normally put on the most fuel-efficient tires.

 

[Escapologist]

It's easy to forget tires being a bit disproportionately disruptive to airflow because the top of the tire is moving forward at twice the road speed, so if it's peeking out of the arch it's making a lot of drag. That's plus any additional rolling resistance from width on the road.

 

[Edge Haley]

It's easy to forget tires being a bit disproportionately disruptive to airflow because the top of the tire is moving forward at twice the road speed, so if it's peeking out of the arch it's making a lot of drag. That's plus any additional rolling resistance from width on the road.

I have a hard time convincing people of this….wind resistance from any car’s front wheels (especially protruding from the wheel arch) have a significant effect on mpg….A pickup truck is NEVER aerodynamic so they need all the help they can get.

I was able to tour the Porsche wind testing tunnel twice in the last 10 years. The last time there, Porsche was subcontracting the latest model Corvette's wind resistance. Porsche is a major source of wind resistance testing for many car manufacturers (even new US models and race cars). They document the levels of resistance with & without plastic deflectors (like front tire deflectors) and different size and width of tires...recommending placement and angle of deflectors for down force, to increase mpg and speed. Consistently fender angles and deflectors are to direct wind flow away from tires. Porsche looks for little things like plastic front tire deflects may produce a 1.0% gain in mpg...it all adds up. Porsche started recommending the front valance idea and fender aerodynamic angles, and almost all vehicle manufacturers have implemented them... Maverick has one, it all adds up.

Their new wind tunnel facility:


More on how proto-types are built and use of 3D-printing.

 

[The Real Maverick]

Third set of tires at 48,000 miles????

I'm on the stock tires that came with the truck at 41,000 miles.

Unnerving to have a MPG drop but air conditioner use at a higher setting than before would do that in a heartbeat.

Do this as a rough test of HV battery capacity if you don't have an OBDII scanner.

Put in Tow Haul mode

Drive around a large mall parking lot or other deserted area at idle. Don't use brake or accelerate unless you have to. 5 minutes will be enough to get your HV battery to maximum 70% charged.

Stop. Leave climate control off. Change mode to Normal or Slippery. Does not matter. Reset a trip odometer. Drive in EV only at about a consistent 25 MPH. Do this without stopping if you can on level ground. If you must stop, stop gently and restart gently. Keep in EV mode for as long as possible. Goal is to drain the HV battery to the minimum allowed in one session.

You should get at least 3 miles.
I can repeat the test and get 3.3 miles every time.

This is how I bench test my HV battery once in a while.

 

[casraipfang]

Thank you for the replies. They are helpful.
I will be replacing my tires soon (as they are already wearing thin) with factory setting again.
To note, I drive a winding mountain road to get to my house and the last mile is dirt road. Both play big factor in the tire wear unfortunately.

Also to note two days ago My Driver side Brake line (Flexible) burst after driving into town. Dealer is wanting to charge $550 for a $30-$60 part..... Wondering now if it is a stuck caliber causing increased heat therefore causing build up of pressure from any water that may be in the line. Still haven't heard what caused the failure as they won't be open till later today.

 

[casraipfang]

Battery replacement at 35k seems odd. Why did it need to be replaced?

Not sure the reason it went bad, but first I noticed the lower gas mileage, then the Engine light come on. When I had them check it out they said it needed to be replaced, under warranty , thankfully.

 

[Techcar]

Thank you for the replies. They are helpful.
I will be replacing my tires soon (as they are already wearing thin) with factory setting again.
To note, I drive a winding mountain road to get to my house and the last mile is dirt road. Both play big factor in the tire wear unfortunately.

Also to note two days ago My Driver side Brake line (Flexible) burst after driving into town. Dealer is wanting to charge $550 for a $30-$60 part..... Wondering now if it is a stuck caliber causing increased heat therefore causing build up of pressure from any water that may be in the line. Still haven't heard what caused the failure as they won't be open till later today.

I would hope the brake line would be covered under warranty ,unless you hit something to break it .

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