99 Lude
Had a check engine light on since Feb. and sometimes the car drops to a pretty low RPM at a stop but it boosts it back no big deal.
Today, the car is stalling out at stops although it easily restarts.


I pulled a code months and months and months ago, I believe it said secondary O2 (although I need to pull it again to make sure).

Is this behavior consistant with what a bad secondary 02 would do?
ANd what would be cost to get it fixed if so?

Thanks as always!