Weird reading on average MPG

[Jmiller11331]

At the time I got out of my truck to run inside for 5 min, my trucks average MPG was 16.0 when I returned it was 15.5. All I did was park (left it running) and ran inside for 5 min. Is this normal?

 

 

Sent from my iPhone using Tapatalk

[btj_z71]

Yes, totally normal. Same thing happens if you're stuck in traffic. I'm pretty sure mine goes down doing remote start too.

 

Sent from my SM-G960U using Tapatalk

 

 

 

 

 

 

[74Sprint17SierraATX]

Depends on what you have it set on, 25, 50 or 400 I believe the settings are. MPG drops pretty quick sitting in these things


Sent from my iPhone using Tapatalk

[nicksoco831]

The average MPG reader on these trucks is way off compared to hand calculations. Just filled up my truck a few minutes ago (5.3, 4x4, 3:42s) dash said average of 20.7 mpg over the 409.3 miles on that tank. Hand calculated came out to be 18.56.

But to answer your question, no this is nothing out of the ordinary, I watch my average go down all the time when I’m sitting in stop and go traffic.


Sent from my iPhone using Tapatalk

[Jmiller11331]

Well it got me thinking because I only have 20,000 miles on the truck and very very recently, I’ve been getting like 13.4 to 14.0 mpg....this is kinda alarming to me because I’m doing nothing different at all and I usually have 17.5 to 18.7 mpg.


Sent from my iPhone using Tapatalk

[Deadpoollane]

Why they have auto off in cars now

 

I’m not agreeing with it, it bugs me when I drive a car with it but apparently it saves a bunch on gas

Sent from my iPhone using Tapatalk

 

[Jmiller11331]

Why they have auto off in cars now
 
I’m not agreeing with it, it bugs me when I drive a car with it but apparently it saves a bunch on gas
Sent from my iPhone using Tapatalk
 

Yeah, I guess it works on saving gas but I don’t have that feature. That’s why I’m wondering why I have such a drop in MPG


Sent from my iPhone using Tapatalk

[rusty503]

You are worrying too much about something that is totally normal. Think about it. The truck is still using fuel while idling but not racking up any additional miles. Do the math.

[Jmiller11331]

You are worrying too much about something that is totally normal. Think about it. The truck is still using fuel while idling but not racking up any additional miles. Do the math.

I understand that now but as far as a major drop in MPG while driving the same route and doing the same thing. I don’t know, probably my imagination idk


Sent from my iPhone using Tapatalk

[NWI Denali]

2 hours ago, nicksoco831 said:

The average MPG reader on these trucks is way off compared to hand calculations. Just filled up my truck a few minutes ago (5.3, 4x4, 3:42s) dash said average of 20.7 mpg over the 409.3 miles on that tank. Hand calculated came out to be 18.56.

But to answer your question, no this is nothing out of the ordinary, I watch my average go down all the time when I’m sitting in stop and go traffic.


Sent from my iPhone using Tapatalk

Mine reads about 8% optimisitc as well. Every time, so it's consistent i suppose at least.

[rusty503]

I was only responding to your first post.

I understand that now but as far as a major drop in MPG while driving the same route and doing the same thing. I don’t know, probably my imagination idk


Sent from my iPhone using Tapatalk

[Jmiller11331]

I was only responding to your first post.

Ok


Sent from my iPhone using Tapatalk

[Sierra Dan]

Our trucks are Sensitive to temperatures.

For example here in Missouri......

During the hotter months May thru August, I average around 17-18mpg with my 5.3 with 3.42 gearing.

This second week of Sept. We are having below average temperatures for the month.

Today the high was 67. Down from an average high temp of about 87.

Right now my average is 15-16mpg.......a drop of wmpg just with a cooler weather change.

So this could explain your mpg average drop if it is cooling off where you live.

And the mpg drop while idling is normal as rusty503 stated.

[sldhead700]

Why they have auto off in cars now
 
I’m not agreeing with it, it bugs me when I drive a car with it but apparently it saves a bunch on gas
Sent from my iPhone using Tapatalk
 

I can't believe that it saves a bunch of gas, probably very little in reality.
It shuts off at a stop sign, and immediately starts back up,? I'm guessing in that situation it probably used more with an in rush on start up?
Not to mention harder on the starter....
Thanks, but no thanks on the automatic shut off.
If I want it off while waiting for a train or long light, I know how to shut it off, I don't need gm doing it for me!

Sent from my Pixel XL using Tapatalk

[hammong]

I wonder if your station got an early delivery of winter blended gasoline -- especially if you're up North.   Winter blend starts nationwide around the middle-end of September, and it most definitely will drop your fuel economy 1-3 mpg.