**SIGH** On to the next delima: lean problems!

[blackbeaSSt]

so now im getting a p0171 and p0174 code thrown at me on the 02 burb. i see there are numerous possibilities of what this could be.

i've changed out the o2 sensor within the past 18 months so im not sold its that. i also see it could have something to do with the fuel pump/filter/etc. i will say that here recently if we let the gas get down to less then a quarter of a tank it seems harder and harder to start. to the point of 2 or 3 times last year it wouldn't start at all unless i put more gas in it.

before i go and drop a lot of money into dropping the tank and replacing the pump, is there anything else that i should try before i hand it off to my mechanic?