MPG slowly dropping

We bought truck last year with 21,000 miles on it. Now at 31,000. Issue is digital mpg showed 15.9 when we bought it. Now as of today digital mpg is 15.1. Slowly continuing to go down. Mostly drive in small town setting. No lead foot. What may be the cause?

 

Short trips kill mpgs... sad but true. In town I average about 14mpg with conservative and aggressive driving.

 

You won't get better mpg in winter. Also check your air filter.

 

I really wouldn’t worry about a variance or .8 mpg over the course of 10k miles. The digital read out isn’t the most accurate either. You could be logging more idle time, more around town, etc. Not to mention atmospheric changes, fuel grade, etc.

 

Change all diff and transfer case oil

 

It seems odd to just keep steadily dropping. The tire pressure light is on. Had Les Schwab put new tires on a few months ago.

 

Same size or 10 ply???

 

Same size tires as before?

 

No bigger.

 

If they’re bigger, there is your MPG discrepancy.

 

You need hand calc or some kinda recalibration to be accurate.

 

Thank you to all of you for quick responses and very helpful feedback!