bad o2 sensor maybe?

ok i hooked my digital A/F gauge up and it reads at the highest 0.10v, sometimes at wide open it reads 0.00v shouldnt it be higher like 0.92v or something. im not getting very good gas mileage, like 130 miles to a full tank which is like 10 gal. i think. i do have a lead foot, but shouldnt it be better than that?
thanks,
tyler

oh and if this matters i dont have a rear o2 sensor i have 2.5" pipe with no cat..

130 miles? You should get way more then that. Your tank is also around 13 gallons. My vote says your O2 is shot. All the ecu will do is just dump fuel in trying to correct it, but to no avail, since it can't. Good Luck.

FWIW, I wouldn't use the o2 voltage as a tuning device, unless it's a wideband.