Gas Mileage

Tom73 · March 13, 2023

I have a 2022 Sierra 1500 Limited with 6.2. Routine trips to visit family of about 1,000 miles round trip I have been getting 19-21 mpg. I consider this very good for a 6.2 liter. But just made the trip again and only got 15 mpg. But a couple days later made a 100 mile trip and got 20 mpg. Mileage is per the onboard computer.

Any idea what happened to only get 15 mpg on a trip that usually gets 20?

newdude · March 13, 2023

Headwinds, speed, traffic, bad batch of gas, weather, etc. Soooo many possible factors here.

Edited March 13, 2023 by newdude

Tom73 · March 13, 2023

1 hour ago, newdude said:

Headwinds, speed, traffic, bad batch of gas, weather, etc. Soooo many possible factors here.

Headwinds, weather: basically same as all other trips.
Speed: about 70-75 as normal.
Traffic: nothing unusual.
Bad batch of gas: could be but topped off 4 times so do not see affecting the overall trip, maybe a portion but not the entire 1,000 miles.

A 25% drop is huge. Hope it does not happen again.

Edited March 13, 2023 by Tom73

GETGONE · March 13, 2023

15mpg is normal for me. Doesn't matter local or highway driving. Best I ever got was 20.5mpg and that was doing 63 on a 2 lane road with the A/C on in summer. Gas does make a difference, octane as well as ethanol content. Winds also make a huge difference. My last trip back from Iowa to Michigan I was doing great heading west to east. As soon as I started to turn north and the winds were at my side, my mileage dropped from 18 down to 15 by the time I made it home, all on the same tank of gas.

Transient · March 13, 2023

I'll also add to the growing list of possibilities the time of year. Cooler temps have air that is more dense. The truck has a bunch of sensors to ensure the engine maintains a 14.7:1 air to fuel ratio. Cooler air means lower mpg.

When these engines have to work they get thirsty. I've had to deal with trips that had a huge amount of wind. I've seen my mpg as low as 10 in areas where I regularly see up to 24.