Would an exhaust leak ahead of the o2 sensor or the sensor itself cause this? I can smell exhaust inside when driving and it kinda sounds like there is a leak but when I get out to check it dies.

(aka suprathepeg, aka Sean)
89 v6 SWB truck "BLACK BEAUTY" EB valves, P&P head 30 over.
95 FZJ80. Lifted. locked and rollin on 33s (my dream machine)