Since you didn't mention the make or model of the vehicle, you will have to look at the following... A lean O2 sensor does not usually mean that the O2 sensor is bad. Since your idle is bad, you need to look at other air/fuel controls such as EGR, MAF, MAP, IA, injector nozzle and anything else that would either restrict air or fuel at idle
I had all sensors replaced in my 03 Trailblazer and the check engine light stiil comes on. Why?
There are sensors all over the engine that can turn the check engine light on.There are sensors all over the engine that can turn the check engine light on.
There are dozens of reasons. But in most cars of this model some sensors just become old and have to be replaced. When sensors fail ECU sets off the check engine light.
CHECK THE TIMING
check your fuel and exhaust sensors to see if they are gummy or have buildup or read the owners manual and take it in the shop for a check up
I have a 98 mystique, and when the check engine light comes on, I simply disconnect the positive battery terminal for a couple of minutes. When I replace it, the check engine light is cleared. It resets the computer.
Then you may want to have a mechanic check it out.
Catalist temp performance poor. Esentially the 02 sensors are reading poor cat performance. It could be the )2 sensors are old and tired but most often it means the Catalist needs to be replaced.
Wrong scanner?? If a check engine light is on, there are codes. Timing sensor? Check engine usually means a problem... Service means that scheduled service needs to be performed like oil change, or timing belt replacement. I would Check your Catalytic Converter. What often happens is the catalyst that is in the Catalytic converter Heats up and Blows out into your Muffler. This means It is not the sensor,but your converter and Muffler Need Replaced.I have just fixed two cars with this problem,and they had the same symptoms,Check engine Light.
There are many sensors that can trip the check engine light to come on.
Oxygen sensors don't have fuses. They either work completely or they don't, and it'll set the check engine light. They can only be replaced.
the check engine light could stay on because of other sensors. for example,the power steering sensor could be bad...this will cause the engine light to come on and other sensors could cause the engine light to come on. just get rid of the van. most sensors when they go bad cost anywhere from $200-$600 just because of the location of the sensor. manufacture put sensors in hard to reach places to keep you from replacing them,so that you will bring it in to dealer and pay over inflated repair cost.