omniprobe

iTrader: (4)

With the car off and the key on the ON position, the gauge jumps around for 20 seconds then settles at 15.5. I don't remember it jumping around that much with the car off.

awdordie

iTrader: (1)

Does it stay at 15.5? Sounds like the sensor is on its way out. If you turn the key to on without starting the car the gauge should bounce around a little then slowly go over to full lean and stay since if the car is off its not reading exhaust just oxygen.

omniprobe

iTrader: (4)

Brand new sensor