Need some help identifying what's killing my mpg

[Ecky]

I've already applied most of those driving techniques effectively, I was hoping P&G would help with the mechanical efficiency though. It surprised me that, so far as I can tell, it hasn't. I'm getting roughly the same mileage, though I'm only able to tell at the end of the tank. I've been trying to be consistent in my driving patterns for the entirety of tanks so I can get an idea of what's effective, until I have instrumentation.

One big surprise was when I pulled a 33mpg tank when I was very rev-happy, playing stoplight hero, and then got 30.5mpg on the next tank shifting much earlier. On both tanks I was still applying good driving techniques as far as light timing and preserving inertia, but on the better mileage tank I was regularly revving 4-6000rpm away from lights and getting to the coasting stage earlier (typically I might only do 2 pulses between lights). I really need an MPGuino to sort this out, I think.