97 grand am 2.4 auto HELP HELP HELP!!!?

Question

car stalling/cutting out,check engine says bad heated o2 sensor,replaced both already...twice actually to make sure parts werent faulty.reset the codes and they come back on after about half an hour of driving.also est off light comes on at same time.what do i do now?

Answer 1

Well Shaun aren't you happy I have the same car and have experienced the same problem.

Believe it or not, the cutting out is being caused by the EST system and not the Heated 02 sensor. I wouldn't have believed it either, but it happened to me. Let me explain why.

The EST is also part of the ABS system. I don't know whether or not your GrandAm is also turning on the ABS light. But what happens is, if a fault is detected it automatically turns off the EST system and most of the time it will Turn on the ABS light. Even playing with the button on the shifter won't turn the EST back on.

So why does it make the engine cut out? Because there is a problem with one of your wheel speed sensors. The same wheel speed sensors that send a signal to the ABS system are also used to tell the PCM if the car is losing traction on take off. For instance, if the vehicle is in the snow and you accelerate and lose traction, the ETS system reduces engine power to allow the wheels to stop spinning and gain traction.

When a wheel speed sensor fails, it sends all kinds of weird signals to the PCM and causes the engine to cut out even when the traction is perfectly fine.You are feeling this as a bad engine cut out on acceleration.

So how do you correct it? You need to determine which wheel speed sensor is failing. On my Grand Am it was one of the front wheel speed sensor. I just replaced both and the engine stopped cutting out. I was very surprised.

As far as your heated 02 sensor code? I can't help you there.  

Answer 2

could be a cracked coil pack i had mine doing that at one time