Sounds like you were using the overhead console for mpg read-out and possibly switched over to paper/pen by actual miles per gas put in the tank.

I have a 2008 QC 4x4. I get maybe 12mpg city and 15highway. Mixed I am about 13-13.5
I drive easy on my truck and rarely get up past 3krpms when driving. Sounds like your mileage is about right. Have you added a handheld tuner into the picture???? that could change things. Your truck is 2wd so maybe you should get a little better mileage than me.
What about tires? Going from stock tires to my LTZ's costed me about 1mpg all around.

 

I've had the Edge tuner since the 2nd week it came out, it's been on my truck for well over a year now. I'm aware that the overhead is not a very accurate, I've been calculating mileage by hand for quite sometime now.

When I got this job and started having to commute everyday, I could normally swing around 410 - 430 miles per tank. That's with it sitting on the "E" pulling into the gas station. I'm now lucky to see 300 miles on the trip meter pulling into the gas station sitting on "E".

Tires were switched @ 40k. Did not see a mileage change when I changed them. And I have checked to make sure they are at the correct pressure.

Back before I started commuting I would've agreed with you that getting 18mpg was a little outlandish. It's the city miles that kills it. Now my truck is driven 99% rural flat highway, cruise set at 59 and I'm telling you 18 was an easy number to get to. Something has changed with my truck, I'm just trying to figure what that is...

 

I have Never seen anywhere close to 400miles from a tank of gas.

Best tank was 330 and that was mostly highway. Generally I get 260-280 for 22gal. 12.7mpg but that's mostly city.

I'm gonna say turn off your A/C and Not run your vehicle to get warm/cool before you get into it to begin your drive.
Those 2 factors alone are gas killers.
Most people forget the fact by having a remote starter diminishes gas mileage. (or going out and starting and leave running) I'll get under 10mpg for the entire tank during winter months as I let my truck run for 20min b4 I get into it sometimes. Summer... I've noticed my mpg's drop using a/c.

 

[quote=bwhite757;1786654]I've got 65k on my truck now, and up until about 50k I could easily get around 18 mpg's going back and forth to work (60 mile commute).

I would kill for 18mpg I am lucky to get 16 hwy. I have gotten used to 12.5 - 13.5, which is why my commute is now on a harley.

 

Dirty air filter? Clogging up cat converter?
My 08 2wd gets about 15 in town and almost 22 on flat 55mph roads.
I average about 18 in mixed driving 70%hwy.

 

+1 on cat.
18 mixed. I can barely get 18 on the hwy and that is keeping it below 65!!

 

400 miles is only 16 mpg if you take it to dead E---> 25 of 26 gallons. If its all hwy miles you could get a little more. 65k on a 2007 is a lot of hwy miles.

 

man i get about 12.5 all city driving and when i take hwy trips i get about 15 the best i ever saw was 16.7mpg going down into kansas doing 80mph think of what i could have done doing 65mph so consider yourself lucky man

 

My gas milage did the same thing... I was getting 20 on the highway - speeds around 60 - for a couple of months and now I am getting 16... I did all sorts of the regular tune up stuff, but no rebound...

 

dirtydog has a good point on "type" of tires. I changed mine around 38K ... went from 265/70 to 285/65 Geolander AT/S. Same diameter tire, maybe a couple of pounds more in weight and certainly more aggressive tread. My mileage was the same for awhile but it seemed that after 1500-2000miles on the tires, my mileage dropped.

I did notice that these tires are quite sticky on the road and have surmised that the tread compound probably has a "dual" nature so that as the tire wears, it maintains a strong traction --- anyway, just my experience.