Question about O2 sencer

I have a 1984 Chevy C10 350 motor, I runs eratic. some time it will idol ok and other times you can't get it to idol enough to take off. if it does idol it is rough and you can smell it is burning rich. you can drive down the road and you have to hit a sweet spot for it to keep runing because it will start bucking and wants to die. then you have to floor it to keep it running. I changed the carb, New points, Plugs and wires. If it dies while running if you take the air cleaner top off there is a lot of Black sandy stuff in the air cleaner. It is a eloctronic carb so I was wondering if it could be the O2 sencer and if so can it be checked or should I just buy a new one. I can't hear any vacume leaks but think I will replace them all just to be safe.  

I'm not a big fan of throwing new parts at a problem, but an O2 sensor is cheap and likely at least part of the problem. The catalytic converter is suspect too. The computer Q-jet carb when working right is not a bad setup at all. There's a ton of reasons, do some research and don't quit till you fix it.  

as far is the cat is concerned I thought that might be the problem also so I dropped the exaust and there was no notisable differance.  

Check if all the fuses are in the fuse box. I had one that the fuse ran the seat belt warning buzzer and the carb and other things .Pull the fuse out and the truck won't run. Mike  

Yeah, always check the fuses that's good one to remember for sure. If a guy had never heard of a computer controlled Quadrajet they'd probably laugh at checking the carburetor fuse... It almost sounds like a muffler bearing, huh?