confusing MPG change

[powerboatr]

I have just a bit over 1k miles on the truck.
around 600 of that is 2 short trips a week 27 miles one way to my doc. 300 ish is highway of sustained over 70, but more like 75 for 50 plus miles one way
100 or so to the dealer 25 miles away at 60- 70 mph farm raod
last week mpg jumped on the doc trip up past 19 and was climbing

today we drove after i filled up with mid grade , got on tollway and ran 72-78 for 50 or so miles and mpg is back at barely 18 (17.8 to 18) , even though the week prior on same trip it was round trip at 19 .
today truck felt sluggish, not missing , just like it was dragging something, this toll way is mostly FLAT with normal over pass climbs at exits, and this trip is was downshifting at each one out of 10 to 8
this was in NORMAL mode, with normal winds and OAT of 103F , engine was at 192 to 199 and trans was 200-212
i did switch to sport for 2 red lights once we got off the toll way to see if it helped he HMMMFP which it did vastly

so big question is what are people getting for real world empty MPG at 70 mph?
i have 3.31 rear gears as well and 4x4 crew cab with a 50 or so lb tool box in the bed. a/c on 65, medium fan

i had a 2013 1st gen eco boost in a 150 crew cab kr 4x4 3.55 , 6 speed it got 19 to 20 at texas speeds of 70 -75 on highway
my 2016 kr 4x4 3.73 gears eco boost expedition got 19 as well and it was 6400lbs
my 2021 superduty 250 4x4 3.31 got 23 at 75 mph. and 17 in town

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[{tpc}]

I see this change in mpg more often than I like. My habits are the same consistently week to week. Usually I’m around 17.5. The other day for fun I switched to eco mode for maybe 20 or so miles. Watched it climb to 17.8.

Thought nothing of it so went back to normal and about my business. Today it was 18.5. How such A big jump in a short time?

 

[Twilighthan]

I had a 2021 F150 platinum and noticed a few times that my highway mpg got stuck just around 17.8mpg. It was weird. The third time it was happening. I pulled over, restarted the vehicle, and things turned back to normal.
I can’t imagine what caused it. I have a 2022 f150 powerboost with 6k miles on it now and never saw this issue.

Something triggers the engine to change how it’s burning fuel and just sticks with it.Usually my fuel was only from Costco or Shell with super unleaded, so bad gas was a low chance.

my normal MPg With the 2021 was usually 24mpg at 65mph on 3 hr road trips. Sometimes higher. That’s why it was easy for me to notice an issue like this.

 

[powerboatr]

I had a 2021 F150 platinum and noticed a few times that my highway mpg got stuck just around 17.8mpg. It was weird. The third time it was happening. I pulled over, restarted the vehicle, and things turned back to normal.
I can’t imagine what caused it. I have a 2022 f150 powerboost with 6k miles on it now and never saw this issue.

Something triggers the engine to change how it’s burning fuel and just sticks with it.Usually my fuel was only from Costco or Shell with super unleaded, so bad gas was a low chance.

my normal MPg With the 2021 was usually 24mpg at 65mph on 3 hr road trips. Sometimes higher. That’s why it was easy for me to notice an issue like this.

and your in austin. so you know what i mean about real speeds
your toll road is really good for putting a load down on the engine.
or toll 49 is 75 all but about 10 miles. but most folks run 77 or more except around 5 pm

i am really going to pay closer attention to my right foot and see what transpires.
its just not a good feeling when the 2021 has the newer gen of eco boost plus all the areo stuff and its getting worse than the expedition or the 13 kr .


yesterday as a note i filled up with 29 gallons and few tenths , this brought me to FULL and i squeezed in a few drops.
DTE read out at 602
i reset trip #2 and off we went, i noticed this morning trip stated 96 miles since i reset it yesterday.
dte read 502, so my math its pretty close to adding up to 602 dte i started with.
this is with the 36 gallon tank.

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