Hi, I'm Brian from Michigan. I've read a few articles on the site in the past and thought it might be beneficial to sign up. I've recently been making an effort to increase the mileage of my car, for financial as well as environmental reasons. My primary vehicle is a '03 Vibe, 1.8L 2WD with 120k on it. Seeing as I work about 38 mi from home, and have to make regular trips to southern Illinois, I log a lot of miles. Luckily, its mostly highway, but it still adds up. I'm in the middle of doing some diagnostics and maintenance to it - got some trouble codes for cylinder misfires, lean mixture, and cat converter efficiency. I figure it can either be a vacuum leak up front, a faulty O2 sensor, or a plugged cat. It currently runs ok, just a little rough when the engine's cold at low idle. The main thing is that my overall mileage had dropped - I used to get about 32/27 regularly, and now the norm is 29/24, although on long highway trips I have gotten up to 43. So, I hope to develop some driving habits that can bump my mileage back up in the short-term, and once this issue is fixed can help in the long-term as well. Unfortunately, most of the areas I have to drive seem to be moderate traffic, so I can't make use of all good techniques. It's pretty much just trying to do what I can, when the opportunity arises.