You know, it's really hard to maintain a really good mpg. In the past, I've been able to get ~450-500 mi on one 16 gallon tank (I'm extreamly aware of this because my 190E only would go 260 to 300mi).
Then, slowly, I've been loosing my range. Last summer, the embarassing situation occured where I ran out of gas
. When that happened, I was exactly at 444mi. That was the summer after I had my DME reprogramed. Odd. Well now, I'm down to only ~400mi on one tank. Just got a bottle of STP fuel system cleaner (cost me over $7.00). I put that funky additive in yesterday. I'm also going to do my best to use a feather on my gas pedal.
To date, after ~70mi, the OBC is saying 28.6mpg, of course that means more like 27mpg.
I guess we'll see how this tank (and the ones that follow) end up.