Gas mileage problem

[izcur]

I have 2002 SLT Yukon with the 5.3 non-flex engine with 68,000 miles. I recently had the right rear axle replaced because it was bent from hydroplaning into a curb. Also the right rear lower control arm was replaced. Since getting it back from the mechanic my gas mileage has fallen off a cliff. I have filled it up twice since getting back and it has gotten worse each time. The most current mileage was 90 miles for a half tank or 6.9 mpg. Tire pressure is good, air filter is clean, no check engine lights, and seems to be running fine. Mechanic says its probably an bad oxygen sensor causing too much fuel to be used. Anybody have any similar problems or have any ideas as to what could be wrong?

 

[denali00]

ouch..i thought mine was bad...u make me feel good bout the crappy mileage i get..i get about 400 a tank...did reaed something today talkin bout bad 02 sensors eating gas up, but that should throw ur ce light ...

 

[00yukongmc]

i get 12-16 mpg no dummy lights on and no mods i have also heard o2 sensor can cause poor fuel economy but i think that would throw a dummy light if it was bad

 

[TunasTwins]

did they check the alignment?

 

[04SS99Denali]

my 03 slt gets 13-14 mostly city driving. my silverado SS gets 11.6 lol but its modified heavily and i beat on it alot. plus it gets track time