Average MPG for me right now is 23.5MPG...not that great for someone who drives about 60-70% highway...but then I do it at speeds around 140kph/87mph (and probably half the time I'm no higher than 5th gear). Sure I'd get better economy if I drove 60mph...but I have to ask, where's the fun in that (if I wanted MPG I would have bought a Prius or an Insight...lol)...
Oh and if there is something "wrong" with tracking fuel economy in excel, then I've got bigger problems...lol. Not only do I track my fuel, ever since I saw one guy's post on DetailCity I've also been tracking all other expenses on my car (sans detailing/cleaning supplies). I was actually able to backtrack all the way back to the original purchase of my car as well, considering I still had all the receipts for parts and service, and my car was only around 6 months old at the time...
