Inspector14 said:
i have changed my driving habits in only a few days due to this thing. i think i may have mis-calibrated the thing tho, since its saying my average mpg for several trips now in town has been only 27-29 mpg, on a 2003 manual.
If your mpg's went down, then you probably put the correction factor in backwards--you probably needed to use the negative % correction, not positive.
On my PD, I found the speed was spot on (indeed, I checked miles traveled vs the odo, and found a 3mile difference after 575miles). But I couldn't wait to get through that first tank of fuel, as it kept telling me I was only getting 34mpg! Correction factor of -26.9%! I'll have to see if now it's correct; but even if it's off by a couple percent, the instantaneous readout and the mpg on the tank info is well worth it.
BTW, I goofed when doing the fuel calibration. The procedure isn't tricky, but I like doing things twice, apparently.
Anyhow, when you go to do the initial calibration, take note of the gallons it thinks it went through, and don't hit "Done". At least I noticed what it thought it burned prior to hitting "Done", so I was able to do a bit of math and still correct it after one tank.