Quick and Easy Like the title says what does the car do when the 0s sensor is bad?

When mine failed it started dumping to much gas into the engine. At higher RPMs the car would stumble and shoot out black smoke.

If you still have the stock ecm and haven't deleted any of the smog program from it, a bad O2 sensor will set a code and turn on the "check engine light."

Most likely start running rich. Hunt at idle. Find out if it's setting a code or check the readings on the O2. When mine died the milivolt's were barely moving....as in not switching b/w high and low mv's during closed loop operation. Good luck!

It set a code 13. Have no idea how to check the o2 sensor though. What tools do I need to check it and what is the process of checking it.

If you mean idling up and down mine does it when I first crank it up. I have noticed it whether engine is cold or hot. It will slowly idle up and down about 2-4 times btwn 800-1300 rpm then it will settle in at 800rpm. I have no idea if the engine has stock internals. I am running a factory ECM and chip though.

The car will sputter under any kinda load. It will do it very easily if the car has been driven about 45 mins or so. If I am easy on the accel it will not sputter if I get on it there will be sputtering and every once in a while it will cut off. When I swaped this engine in I put new cap, icm, plugs and wires, O2 sensor fuel pump, fuel filter, coil and I am probaby forgeting something.

I guess it could happen with a new one but do you think the o2 sensor is bad? After all the ecm is telling something is going on with it. Also could this cause the sputtering problems I am having?

Need more input guys. Let me know what you think b/c this is a daily driver!