Large Jump in MPG per Scan Gauge?

Why am I all of a sudden getting better fuel milage? I usually average with mixed driving 16-17 mpg per Scan Gauge. That is with an admittedly heavy foot. Well starting yesterday I noticed at the end of a drive I make all the time I had 20.x mpg when I pulled into the garage.

Today doing some running around town even trying to make it go down by being even more heavy footed, I got 20.9 in mixed driving.

No Codes have ever popped up in the months I've had it. But it's as if something fixed itself by unclogging, unsticking or something. I'm not going to complain at all if it is accurate. I'll have to do the math on my next fillup and see if maybe there's a problem with the gauge. I double checked the settings for engine displacement and I am watching the MPG as well as the AVE. It is very strange.

Any ideas?

 

I'd def hand calculate it. You can get an app that does it for you.

I had an Autometer mpg meter that plugged into the odbII port and it was reading way more mpgs than I was actually getting. Could be the same with the scangauge, but it's weird that it jumped all the sudden.

 

How many tanks have you gone through with the scangauge? I'd say after 5 or so fillups my MPG started getting less "great" and more into the "alarming" area lol

 

I've had it for 6 months. And it's been consistent. I've verified the engine displacement at 3.4 and tank capacity at 18 gal. I thought maybe my two year old son was pressing buttons. I put him in the drivers seat to play when I'm in the garage. He pulls levers and presses buttons and turns knobs.

But he hasn't been in there in a while and I went through the settings. Displacement is really the only thing that I think could effect mpg. There really isn't more than that in the setup than this and I've had it for a while now. It's weird.

I'll do the math when it's empty to see if it's close. It's just mileage/gal. But it's still strange. These are routes I take all the time.

 

I thought that when you do a fill up, it says fuel used 15.8 (or whatever) then I look and see I added 15.68 (close enough). It was all good. It tells me how much I used and I tell it (if needed) how much I've added. And the cost for CPM calculations. That's how it knows what it's working with. It knows how much is being delivered from the CPU.

So let's say I tell it I've added 27 gallons, it will only affect the miles till empty and projected miles left in the tank. The MPGs should be the same regardless. Am I right?

 

You could be right I'll keep on truckin and set it up again....till then I'll enjoy my extra MPG!

 

Fuelly is a great app to use in conjunction with your Scan Guage to calculate your mileage.

 

You have to correct, enter and save actual gallons used for at least a few consecutive fill up's to calibrate the Scan gauge then it will show very close to correct MPG but the average is reset every time you start the engine so it is only accurate for longer trips. This is explained in manual.

 

Side note, just drove to the shooting range. 20 mpg. But the instant mpg shows a sizable increase cruising down the freeway at the usual 70 mph. So strange...

 

Yeah I understand that. It's calibrated per the manual and it's only off by a tenth or two during fill ups, which I usually correct if it's more than .25 gal or so due to different pumps and all. I'm comparing apples to apples. These are the same places I usually go, same trip duration and distance. These readings aren't the same as what I'm used to for these type of trips...

Went for a trip to wheel about 2 hours out of town a few weeks ago and still averaged 16.x mpg all hwy.

 

I reset trip meter and record miles and gallons each fill up a as well as reset and save fuel used on scan gauge and when I get home calculate fuel mileage the old fashioned way. My scan gauge showing right at 20 mpg average and hand calculation 19.89xxxx 2014 DC SB TRD OR V6 short bed with ARE Z series shell

 

I do the same, and compared for a few tanks to see if scan gauge was accurate. It was close enough to trust for me. I just filled up the other day and will do the same later this week. I appreciate the replies guys. It's just odd. It's almost as if an egr valve unclogged or a some sensor reset or something. I know that's not what happened as I would have thrown a code but it even seems to drive different. (Could be psychologically induced by the better readings. Lol)