I just got my first tank results. 290 miles from 15 gallons. This is with about 70% highway, 30% city driving. This equates to just shy of 20 mpg. I believe that this is a little low for what you guys are suggesting as to fuel economy. Should this be close to what I'd be getting if it was all city driving? Please advise.

Guess its time to put a new fuel filter on and find somebody with a scan tool to see what this O2 sensor is doing. My girlfriend has a 94' 88 and its fuel economy is similar to what I just got, so who knows. With gas headed to $4.00/gal, I want to make sure this thing runs like a top. Its sad when you have an LS1 that has almost a 2 liter soda bottle'* worth more displacement amongst two more cylinders and it gets better gas mileage than this.