time for a new O2 sensor?

[HYBRIDxS13]

i have an s13 sr20det and a autometer air/fuel ratio gauge installed. i know some of u will say its a useless light show. anyways the signal is suppose to bounce back and forth in the stoich region and go to rich at WOT. it use to do that but now it just stays still at the same stoich point and goes lean at WOT. does this mean my O2 sensor is bad and not sending the right signal causing my car to run poor/too rich with a pre-defined fuel map to prevent running too lean.

is it time for a new O2 sensor? i found stock sr20det O2 sensors for about $80. i don't really want to buy a new one unless its the most likely cause my gauge is getting a bad reading. i also double checked all my wiring and it looks OK to me.

[180fan]

you've a redtop, get the o2 from pdm. you're lucky since they've found a match for your o2 i've a blacktop and can't use that. they've got em for like 40 somethin bucks. might just want to change it anyway

[navysnail]

if your o2 sensor is bad, the ecu will switch to safe mode (always rich). check your fuel pressure