Ok lately I have be having some shitty gas mileage "while not even getting in boost".
I probably get 300 max per tank. My fuel gauge and miles till empty and MPG gauge are both messed up. how i know this is when I fill my tank, the highest it ever reads is a little above 3/4 tank. The first 1/4 of a tank I get like 70 miles the 2nd I get probably 70 and the last 1/4 I get over 100vbefore it starts reading "----" in the Miles till emptyIt probably can go longer but i dont feeel lik testing it and running out of gas. ...Now with the MPG gauge its horrible it reads while driving around in the city I get 29MPG and if i reset it on the highway it goes up to about 50..I know there is no way in hell i get that...My question is what is causing this Is it a bad O2 sensor?
also My A/f Is fine, usually between 14 and 15 while driving in 0 load column on Utec

 

are you running a completely stock fuel system?

 

sounds like your level floater is not working properly, could be damaged from taking the pump in and out or being interfered with by the wiring inside the tank.

Don't go by the computer, with the larger injectors it is off, I would actually use old school method of a calculator and calculate your own mpg

 

+1, That is the only way to do it.