I'm trying to pinpoint my gas mileage based on the 15.3 gallon tank
capaciy.
I have filled up the tank twice since purchasing my 02 CRV-EX/Auto.
I drove the car until the fuel tank light came on both times and
continued to drive with the light on for maybe 15 or 20 miles longer
so that I could get as close to empty as possible.
On both occasions I filled up until the nozzle fill up automatically
stopped. I did not top off off the tank, since I've read this is not
good.
It took 13 gallons both times until the automotic nozzle stop kicked
in. On each occasion i had gone 310-315 miles before refuelling.
Can I assume that the tank will take another 2 gallons to top off
completely or did I still have 2 gallons of driving left after the
fuel tank light was on continuously for 10 or 15 miles.
I think the latter was likely. If true and I had 2 gallons left to
burn, or maybe 40 miles, then I would have gobe about 350 per 15.3
gallon tank
or about 23 miles/gallon on 50/50 city and highway driving.

My 2000 CRV 5 speed has the exact same mileage as yours. Of course results
depends on your highway speed, too. Last night I was running between 70-80
mph when the light came. I went another 7 miles to a gas station and it
took 13.gals, topped off. I guess it's nice to know there's 2 gal left. I
usually start looking for a decent price per gallon ($1.06 this week) when I
get to 300 miles on the tank.