SES light

Hello all, I've been a post reader for a while, however, just joined today. My daughter has a 99 SC2 that was hesitating a little when she got to about 40mph. She took it to a shop and they said it was the coil pack. I replaced one pack and the problem contiued so I switched it with the other pack. No change. Next I changed the spark plugs, air filter, EGR valve, ETC, cleaned throttle body. Now the car hesitates at about 30mph. Autozone ran the code and turned out to be the O2 sensor. Bought and replaced front sensor, assumable reset pcm by disconecting battery and pulling fuses. Car still hesitates around 30mph. In fact, while your driving, as you give it a little gas, the SES flashes and you feel the car hesitate, but you can't accelerate, rpm's don't raise.
I took the O2 sensor off and returned it to Autozone. My plan is to change the fuel filter/pressure regulator however, no part stores in town stock it.
Anybody have any other suggestions? I've already spent more money than my daughter can afford to pay.
Thanks

I would buy an o2 sensor directly from saturn at www.saturnparts.net just cuz the o2 sensor tends to be one of those "only get OEM" kind of parts. I don't think you need to mess with the fuel pressure regulator either. You should also post all the current codes that you have.

To add the codes can not be cleared by a battery disconnect.
You need a scanner to clear codes.
Also a code does not say replace the sensor they say check it out.
A flashing light may point to a cylinder missfire.
As stated in upper check and post post back code no.
Then clear codes with a scanner and see idfany or what ones return.
What is the mileage on plugs and fuel filter?
MT

Also a code does not say replace the sensor they say check it out.
A flashing light may point to a cylinder missfire.
MT
Generally, if there is ANY issue with the o2 sensor, it's best to replace it. I also believe you may be experiencing a misfire. What brand spark plugs did you use? You should NOT be using platinum plugs of any kind most important. NGK v-power is the ones you SHOULD use.

Thanks, I bought the O2 sensor, but checked the spark plugs before replacing it. Sure enough I had bought an installed platinum plugs about a month ago. Replaced them with the alternate and car runs great for the first time in months. Went back to Autozone, had them clear the codes although it still says bank one O2 sensor defective, light is still off, car runs, and I returned to O2 sensor again.

Thanks everyone

Craig


Generally, if there is ANY issue with the o2 sensor, it's best to replace it. I also believe you may be experiencing a misfire. What brand spark plugs did you use? You should NOT be using platinum plugs of any kind most important. NGK v-power is the ones you SHOULD use.

If the light does not come back on after code clear you do not have a problem.
A code or any code does not say the 02 sensor is defective.
What was the code no you had when they cleared it?
The code no would tell us a lot about what is going on.
Post back the code no and let us know if the light comes back on>
Also depending on the code it may need the EE prom reprogramming. And a 02 sensor replaced
There is a tsb on it.
MT

I'm sorry you had to spend a bunch of money for what was a simple probelm. Putting in platinum plugs is actually a common mistake people do to their saturns. Most of those thing that you did are good things to do to saturns anyway though so you should have years of faithful service from it.

with the exhaust manfold cold, remove the front O2 sensor, and test drive, if power increases. a clogged cat is possible, if so, and you have less then 80K miles, take it to saturn, it may be warrenty. do not drive with the O2 removed any more then is needed to diagnose, do not reinstalled the O2 with the Manifold hot.