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

[ScottyC]

....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 cheapest tires.

Fixed

Sponsored

 

[Hot Runr Guy]

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.
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 invented the front valance idea, and almost all vehicle manufacturers have implemented them... Maverick has one, it all adds up.

After having (2) MY24 Lariat 2.0 EB's, both AWD/4WD, with the 2nd being a Tremor, I've often wondered if the 1" higher profile, and the wide-open lower bumper, are the major contributing factors to a 4-5 highway mpg difference between the 2. As well as the difference between the AT and non-AT tires.

HRG

 

[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

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.

wow! well perhaps those two things are related - the possibility that a caliper was seized or rubbing and that the internals of the hose were disintegrating - I found this - I'd suggest that they/you check that broken hose and see if the inside wall shows some shedding debris - also they should check the brakes associated with that line - they may now find that the caliper is NOW not seized due to the fluid being released thereby freeing up the caliper but they can for sure look at the pads and see how much they have worn.
" Internal wall disintegration – Strips of internal wall rubber peel away and float in the current of brake fluid. The rubber strips allow fluid into the caliper, but as the fluid leaves, the tethered strips block its exit trapping the fluid and causing the caliper to stick. "

 

[Phimosis]

Porsche invented the front valance idea, and almost all vehicle manufacturers have implemented them... Maverick has one, it all adds up.

Yup, in 1971, Porsche started copying Chevy’s use of the front valance from the 1966 Corvair. But they didn’t do it for gas mileage, they did it to reduce front lift since they are rear engine cars, the front is already light and they tend to understeer on throttle.

 

[Timothyd]

Fixed

Yeah, tires matter. I get less milage in the winter with the snow tires plus the colder weather. 40-42 mpg winter/48-50 mpg summer. Till it got hot and started using AC.

 

[Phimosis]

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

Yeah, you’ve got too many variables going on to know exactly what is causing what.

Reverting back to all stock would let you know if it is the mods to your truck, or if something is actually wrong with it.

Quick chat GPT search says that removing the engine “splash tray” can cost 1-3 mpg.

Your description of the problem sounds almost like regen braking is not working, similar to when the battery went bad. Did you try testing city vs highway mileage? If you’re getting like 25 city and 35 highway, then for sure, it is not storing the regenerated energy.

 

[Jonny44]

What is the ambient outdoor temperature? My MPGs drop like a brick anytime the outside temperature drops below 25f or raises above 95f (WITH the HVAC off). The battery seems happiest at about 70f.

 

[Edge Haley]

Yup, in 1971, Porsche started copying Chevy’s use of the front valance from the 1966 Corvair. But they didn’t do it for gas mileage, they did it to reduce front lift since they are rear engine cars, the front is already light and they tend to understeer on throttle.

I didn't know a Corvair could have enough speed to need a valance. My college roommate loved his Corvairs, had 3 of them. The Porsche 911 Turbo (with the valance & tail) published the weight down force at 60, 70, 80, 90 + MPH in the owner's manual. At 60 mph it was like 60 lbs of down force (on the rear wheels) and 120 mph it was something like 380 lbs of down force....The effects of a valance and rear tale were very noticeable to a driver as the car lowered at speeds, and significantly effecting tire grip on front and rear wheels. I had a 1949 356 Coupe and it had a factory installed valance. There was never a known patent for a valance but they have been around since the 1930's, pretty much every car maker now has them.

 

[Phimosis]

I didn't know a Corvair could have enough speed to need a valance. My college roommate loved his Corvairs, had 3 of them. The Porsche 911 Turbo (with the valance & tail) published the weight down force at 60, 70, 80, 90 + MPH in the owner's manual. At 60 mph it was like 60 lbs of down force (on the rear wheels) and 120 mph it was something like 380 lbs of down force....The effects of a valance and rear tale were very noticeable to a driver as the car lowered at speeds, and significantly effecting tire grip on front and rear wheels. I had a 1949 356 Coupe and it had a factory installed valance. There was never a known patent for a valance but they have been around since the 1930's, pretty much every car maker now has them.

Yeah, the turbocharged 2.7 liter flat 6 in the 1966 corvair made 180 hp and was more powerful than any road going cars that Porsche made in that era.

The 1949 356 didn’t come with, or have an option for a front valance. The first Porsche to have one was the 1969 916 prototype, but it didn’t make it to production. The first production Porsche with a front valance was the 1971 911 S.

This was quite a few years after the stock corvairs were using them.

 

[Sykotyk]

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.

I'm at 60k and original tires with tread to spare. No way would I accept having to get another new set already by 60k.

 

[casraipfang]

wow! well perhaps those two things are related - the possibility that a caliper was seized or rubbing and that the internals of the hose were disintegrating - I found this - I'd suggest that they/you check that broken hose and see if the inside wall shows some shedding debris - also they should check the brakes associated with that line - they may not find that the caliper is NOW not seized due to the fluid being released thereby freeing up the caliper but they can for sure look at the pads and see how much they have worn.
" Internal wall disintegration – Strips of internal wall rubber peel away and float in the current of brake fluid. The rubber strips allow fluid into the caliper, but as the fluid leaves, the tethered strips block its exit trapping the fluid and causing the caliper to stick. "

I just picked up the truck from the dealer, going to install new brake line myself. They told me the line sprayed brake fluid from both ends of the hose. Printed out the paper indicating that it is indeed not covered by warranty. Gave me the number to call Ford to dispute.

Going to remove hose and take pictures. will update when new part arrives.

 

[casraipfang]

I'm at 60k and original tires with tread to spare. No way would I accept having to get another new set already by 60k.

I drive winding mountain road and part of it is dirt, unfortunately both have a drastic effect on tires. even the tires for my mirage only last a year or 30,000 miles. I will be checking alignment after I get new set of tires

 

[casraipfang]

What is the ambient outdoor temperature? My MPGs drop like a brick anytime the outside temperature drops below 25f or raises above 95f (WITH the HVAC off). The battery seems happiest at about 70f.

The temp hasn't played into any of the issues, as I bought the truck in Feb of 2024 and the mileage didn't begin to drop until the following Jan-Feb and stayed low from Feb through present

 

[Escapologist]

The problem with unsealed roads, dirt, gravel etc, is that even if you drive the same road all the time, you're not driving the same road all the time. Traffic, weather, seasons are all changing the surface rapidly. Hard packed and "polished" would be the optimum for least rolling resistance, but just running in a quarter inch of dust on top of that would be different, by the time it's half an inch it's as bad as fresh snow. Then if it rains and turns it to mud, your tires are doing as much pumping as rolling. Dries out a bit and you're doing good, apart from it's still a bit soft and somewhere up or down needs construction materials and then a load of heavy trucks make it all rough and washboardy. So now the average surface a lot rougher, takes ages to pack in again, or just gets worse.... So yeah "same road" not same surface.

 

[pigsareus]

I just picked up the truck from the dealer, going to install new brake line myself. They told me the line sprayed brake fluid from both ends of the hose. Printed out the paper indicating that it is indeed not covered by warranty. Gave me the number to call Ford to dispute.

Going to remove hose and take pictures. will update when new part arrives.

good idea for sure - you might also want to blow some air thru the hose and see if any shreds of rubber come out. If there is internal disintegration you can fight the Ford battle. It's very peculiar that the hose leaked at both end that seems like at a minimum the fittings were not secured properly. Good luck.

Sponsored