Disappointing 31.5 mpg on 850 miles trip: LA-Arizona-LA

[Sylvester]

As I took delivery of my Maverick in December last year, the gas mileage was great. With the first tank I almost got 600 miles and moving forward I was averaging always 40mpg+. I had done all the software updates 2 or 3 weeks ago and noticed that the city mpg had gone down significantly but my overall mpg on my last tank of gas seemed to be unchanged. I still got great gas mileage when I drove freeway routes within LA. In the meantime I have 8k miles on the truck.
Now I took my first longer trip and drove with my Dad from LA to Arizona (a small town around 80-90 miles beyond phoenix) and back in one day. Total of 850 miles. The gas mileage was super disappointing. I got around 31.5 mpg average on this trip. I don't know if it was the strong side wind, the fact that I had my dad in the truck (I usually drive alone) or the fact I had to go up and down the hill, but this is not what I am used from this truck on the freeway. Until now, I actually got the higher mpg on the 30-40 mile trips of the freeway. I would get 50 or 60 mpg on some of my freeway rides. Anyone an idea what was happening here?

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[Bad Actor]

I wouldn't sweat it. Density altitude, vehicle weight, quality of fuel, wind, altitude change and even road surface can all affect mileage.

 

[flyking1]

I read in another thread that high ambient temperatures can decrease hybrid MPG. The truck relies on the gas engine more in high temps.

 

[TE37Mav]

Seems normal. I’m in SoCal to. And freeway miles here are more like city miles with all the traffic. On long trips like that the battery has no situations to recharge and at higher hwy speeds it’ll run purely on gas engine. Gotta remember it’s rated 33 hwy so your not far off from where it should be.

 

[Doug Wildman]

I got 35.5 on 1700 mile road trip to Louisiana. I’m getting 41.5 around town in the last 900 miles. For reference, I fill up with 93 octane.

 

[icegradner]

I read in another thread that high ambient temperatures can decrease hybrid MPG. The truck relies on the gas engine more in high temps.

Not sure about that, never had any issues with heat in and of itself in my non-Ford hybrid. Now using AC more, the AC compressor would have to work harder in higher temps, could very well be the cause.

The OP also mentioned wind, which can have a big impact on fuel economy.

 

[Snax]

A few thoughts:

To get the best efficiency with a hybrid, the traction battery needs to be charged with regenerative braking (either gently applying the brake pedal, descending hills, or letting up on the gas). No regen = no power = no electric miles. On long road trips, with really consistent speeds, you may not be putting much energy into the battery, so the gas engine may run more. It's also hard to slow down quickly on the interstate with just regenerative braking, so it's easy to lose a bunch of potential power in aggressive stop-and-go traffic.

Another possibility may be the winds that you mention. While the electric motor can push the truck along at 65+ mph with light loads, the crosswinds may be adding enough load that the ICE needs to run more of the time.

I've found that I can get 40-50 MPG on the interstate in ideal conditions: no/light winds, warm weather, some gentle hills, and 65-75 MPH. But with poor conditions (rain, wind, no changes in speed, steep hills, hard braking, 75-80 MPH), I get 30-40 MPG.

 

[projectvortex]

As I took delivery of my Maverick in December last year, the gas mileage was great. With the first tank I almost got 600 miles and moving forward I was averaging always 40mpg+. I had done all the software updates 2 or 3 weeks ago and noticed that the city mpg had gone down significantly but my overall mpg on my last tank of gas seemed to be unchanged. I still got great gas mileage when I drove freeway routes within LA. In the meantime I have 8k miles on the truck.
Now I took my first longer trip and drove with my Dad from LA to Arizona (a small town around 80-90 miles beyond phoenix) and back in one day. Total of 850 miles. The gas mileage was super disappointing. I got around 31.5 mpg average on this trip. I don't know if it was the strong side wind, the fact that I had my dad in the truck (I usually drive alone) or the fact I had to go up and down the hill, but this is not what I am used from this truck on the freeway. Until now, I actually got the higher mpg on the 30-40 mile trips of the freeway. I would get 50 or 60 mpg on some of my freeway rides. Anyone an idea what was happening here?

How fast were you going?

 

[Sylvester]

How fast were you going?

I think I was pretty fast. I usually go 65ish on the freeway. During this trip, the freeway had 75miles/hour limit on many sections, so I would go 75ish. One other difference to my "regular" freeway trips was, that here I was on cruise control most of the time. At home, I usually play with the gas pedal a lot and do "one pedal driving".
On my way back, the mpg was hardly 30 and it really frustrated me. Even with my last 6cylinder infiniti q50 I would get 35mpg under similar conditions. I guess I have been too spoiled thus far with my hybrid. When I drive LA Ventura, with light to no traffic, the conditions are pretty similar and I get nearly 50mpg. I am still trying to figure out if this is the aftermath of the software updates (PCM for rough idle TSB 22-2124 and trailer brake) or just all the conditions I described above. I will reset all the values and see how things go when I am back to normal driving.

 

[Jah.]

Trailer brake software update only on 4k tow package .

 

[TE37Mav]

I think I was pretty fast. I usually go 65ish on the freeway. During this trip, the freeway had 75miles/hour limit on many sections, so I would go 75ish. One other difference to my "regular" freeway trips was, that here I was on cruise control most of the time. At home, I usually play with the gas pedal a lot and do "one pedal driving".
On my way back, the mpg was hardly 30 and it really frustrated me. Even with my last 6cylinder infiniti q50 I would get 35mpg under similar conditions. I guess I have been too spoiled thus far with my hybrid. When I drive LA Ventura, with light to no traffic, the conditions are pretty similar and I get nearly 50mpg. I am still trying to figure out if this is the aftermath of the software updates (PCM for rough idle TSB 22-2124 and trailer brake) or just all the conditions I described above. I will reset all the values and see how things go when I am back to normal driving.

Think you need to remember these are rated at 33 hwy
So yea you’ve probably been driving in favorable conditions to get above rated mpg.

 

[projectvortex]

I think I was pretty fast. I usually go 65ish on the freeway. During this trip, the freeway had 75miles/hour limit on many sections, so I would go 75ish. One other difference to my "regular" freeway trips was, that here I was on cruise control most of the time. At home, I usually play with the gas pedal a lot and do "one pedal driving".
On my way back, the mpg was hardly 30 and it really frustrated me. Even with my last 6cylinder infiniti q50 I would get 35mpg under similar conditions. I guess I have been too spoiled thus far with my hybrid. When I drive LA Ventura, with light to no traffic, the conditions are pretty similar and I get nearly 50mpg. I am still trying to figure out if this is the aftermath of the software updates (PCM for rough idle TSB 22-2124 and trailer brake) or just all the conditions I described above. I will reset all the values and see how things go when I am back to normal driving.

If going 75 in extreme heat I’d say 30 is about right. I notice a huge difference between 70 and 72 or 73 at times, all other things being equal. The EPA numbers of course are at 70 and I’m sure not at 110F. I’ve had other hybrids before but this one seems particularly sensitive to cold and heat which may be due to its battery being exposed more as others have said.

 

[Sylvester]

Trailer brake software update only on 4k tow package .

I am not sure if it was the trailer brake or just trailer software update, but I they told me they had to update the trailer software. The system was showing that there was an update available as I asked them to update everything what needed an update (which was stupid and I would never do again)

 

[Rob Cactus Gray]

Seems like good numbers to me. My Prius dived to 37MPG at 80MPH from 45MPG in city. I used to get nearly 44/50 but those days are long gone

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