here's some better data, my notes from January when I first installed the Hypertech.
The MPG from my last 8 fillups with straight city driving were (from Sept to Jan) 10.37, 10.01, 10.37, 10.43, 10.17, 9.5, 9.17, 9.04 (MIL tripped a P0138, still haven't replaced the rear O<sub>2</sub> sensor but I think this is why it was getting 9 mpg), 10.60 and 10.05. After Hypertech, strictly in town, 11.0! That was a solid 1 mpg gain.
The MPG from my last 7 all highway tanks were (from May to Jan) 13.31, 13.49, 13.59, 13.20, 12.90, 13.04, 13.36. After Hypertech, all highway, 15.04! A solid gain in mpg as well. This last trip was with the wife and 4 kids (drove to Luxembourg and back today, all highway, 75mph.) I have only exceeded 15 mpg 3 times that I know in the past 4 yrs of owning this (two ventures into the low 16 mpg are and one tailwind assisted, no passenger, flatland 17.2 mpg freak of nature) and the 13s are the norm for me on the highway.
I'm happy with the in town gains, it didn't shift out of OD as much today doing the hill climbs east of Kaiserslautern approaching the French border (I drove this same route last month enroute to Paris) so that was noticeable. Throttle response and 20-50mph improvements noticed.
Notes from April:
Over the last three tanks, mileage has continued to increase. First two tanks with 75 miles of highway and 175 city were 12.9 mpg and the last with 246 all city miles was 12.2 mpg which is a good improvement from where I was in December. Haven't cleaned the filter or changed the oil since installing this. It's definitely one of my better investments!
