wierd sensor setup

my 95 k1500 keeps burning up oxygen sensors and i was wondering if it had anything to do with the fact that the manuals all say it has a two-sensor system and the only one i have is the one right before the cat. anyone have this one-sensor setup also? the exhaust appears stock

my 90 K1500 only has 1 02 sensor. Pretty sure all of the TBI engines only have 1.

//2000CAYukon

What engine and transmission?
What code no is it setting?
Is it melting down the sensor or how is it burning it up?
MT

well, its a 4.3 with the car-style 5 speed that requires that you use first gear to start out. it just seems to be plugging the sensor up with soot and whatnot. the code was for lean oxygen i believe, or simply put, running rich