tripps

iTrader: (7)

Just got a tune on my bolt-on only 99 T/A, and the tuner said that my o2's were bad and were dumping alot of fuel, causing my bad gas mileage. But if I had bad o2's wouldn't i get a check-engine light or anything? Occasionally I'll get a SES light but then will go off the next day.

The tune and dyno showed i had 331rwhp/342 rwtq. Any help is greatly appreciated. About to go on a roadtrip and I need the best mileage I can get!

trans99am

iTrader: (1)

wont hurt to replace

cruzc5frc

iTrader: (1)

what codes are thrown when ses goes on?

sroach20

iTrader: (31)

o2s don't generally trip the ses light until they get really bad. after i changed my two fronts (no light) my gas mileage skyrocketed.

Frost

iTrader: (45)

One of the problems with them is that over time, they drift, and that doesn't set a code. I change them in all of my vehicles at a maximum of every 20K miles, much less in my TA.

tripps

iTrader: (7)

Oh wow then I definitely need to change mine out, i bought the car 3 1/2 years ago with 79k miles and it now has 119k and I've never changed them! I'm not sure what codes were thrown but I'm pretty sure it was due to the !AIR and !EGR and no back o2 sensors since it was before the tune, but the light would only stay on a max of 1 day.

If they haven't been changed since factory then I'm buying two new ones tomorrow! They are usually around 80 bucks a piece right? Thanks for all the help! Gas mileage is horrible right now.