Oh, and what's your altitude? Where I live is around 2500 ft above sea level.

Well seems that all of you guys are getting good milage, I'll have to do the hand calculations to make sure the UG is correct but here are the numbers I have calculated by UG:

Altitude - 7200' ASL
City - 10.6
Hwy - 12.2

I use just generic 91 Octane with ethanol from Kings Sooper, I'll try a tank from Shell see if that changes in comparison with a tank from King Sooper. Also does the Sea Foam work as a gas additive?? Never tried it.

Cheers!

Looks like Chicago is 575 feet above sea level. I run standard plug wires and champion copper core plugs

After my next fill up I think I'll switch to the copper plugs and see if that helps much or any. Also gonna try a tank of no ethanol 93 octane, but that will be after I've tried copper plugs for a tank so I can conclusively see which makes what difference, if any.

I averaged about 15.7 on my DashCommand app driving from Syracuse NY to South Jersey... I was running Wawa 92 octane gas from NJ. On the way back, I averaged about 12.6 on 93 octane Sunoco. Considerably lower mileage, but I've since developed a small vacuum leak so I think it's dropping my mileage pretty heavily. Running pretty much stock, with an electric fan added that's about it.

04,,D2,, 4.6 on a 2100 mile trip 4 adults cargo space full ,,
Factory brush guard & sidesteps , AC running whole time, ambiant temp 80 to 100,, 255/55/18 terra Grappler tires, champion platinum spark plugs , 8mm blue wires,,
engine oil Mobil1 0w40, gear/diff oil Mobil1 75w90, Trans fluid Maxlife synthetic Dex/merc,
Average 16.7mpg, doing 75-80 mph, diff premium gas 91-93 depending what was available,(best mpg when adding "Gumout complete fuel system cleaner" to tank)
best when daughter driving 17.8mpg,,worst when son driving 15mpg,
maybe road condition also had something to do with it uphill/downhill , flat,
But she got better mpg because would keep very good constant speed,
In city lots of stop & go average speed 35mph around 10-12mpg or worse ,

The 110 would probably do better if I had overdrive so the RPM wasn't so high. Of course if I had a over drive I would probably drive faster than 55 mph.

I have a stock 04 SE that gets 13-14MPG. I mostly drive in the city. I'm using Castrol GTX 10W-40 and Bosch plugs. I only use Shell VPower 91 octane.

1998 Disco I, get 15-17 mpg. On some long freeway trips, I've gotten up to 18.5 mpg per tankful. Thats dividing the miles by the fuel I put into the tank. But around here general driving, 15mpg.

As I read your post, I'm trying to figure out why you have 400 lbs of tools and parts you are carrying around? That's eating into your mileage. Try getting rid of all your excess weight including the jack and any tall carriers, see what that does. The old MAF might have something to do with it. When I changed the MAF on my Jetta TDI it went from barely running (not throwing codes) to running like new with full power restored. I had cleaned it multiple times with MAF cleaner too and that didn't help. It's worth considering replacing.

Alex I think your trip counter can't be accurate if you have larger tires... Also if your tires are larger that means the circumference of the tire is larger meaning you travel a larger distance than what your counter will measure as a completed turn. Maybe I'm wrong I don't know if you have had things calibrated right. I have stock 03discovery hse7 I don't carry a heavy load I average 15-16 I don't speed crazy nothing over 75. I only use 93octane.