Is it possibile to burn up an oxygen sensor? rpms up and down

[sxchatt]

My "91 240 sx rpms were jumping up and down sometimes dropping out completely when slowing down. I changed the oxygen sensor and it helped for about a year now the problem is back suddenly. Should I replace it again? Can you tell by looking if it is fried? I'm fairly new and not very good at this but maybe you can help anyway? THanks

[LayNLow240]

Need more information. Does it happen only at idle, or is it under xx rpm, or what?

[swatteamtimmah]

Ive never heard of an bad oxygen sensor doing that....

[sxchatt]

They jumps and down wildly on deacceration and stopping and now it has started dying when stopped or close to stopping. YOu have to keep foot on the pedal to keep the rpms high enough when idling so that it does not die. I changed O sensor a year ago and did some other things (tune up,etc..) and the problem went away totally. Returned suddenly. Someone suggested idle air circuit but unsure what that is Thanks!