Hi all,

I am new to this forum and also new to Saturn. As a European in the US I decided to purchase an SL2 as it seemed a good deal. It has been great so far, but recently the service engine soon light has turned on with the following codes:

p0133 - slow response heated oxygen sensor bank 1
p0304 - cylinder 4 misfire detected

I have had the car for about a week now and it is running fine. The idle seems a little more rough when the engine is cold but it is hardly noticable. Also, the RPM are normal and the car does not stutter on acceleration. The spark plugs have recently been changed by the previous owner and he has used the original NGK model that Saturn used in 1997.

It seems to be doing a little worse on gas than I expected, but this may just be psychological as my previous car was a 1.3 L Suzuki Swift that hit 38 MPG.

The ses light went off the other day after I pulled the ignition wires and connected them again. It came on again this morning when I was driving to work. I will stop by autozone tomorrow to have them check if it is giving the same codes as it did the first time I went there, but I am guessing that this will be the case. It did pass NC OBD-II emissions inspection after the light went off the first time, so I don't think it is something substantial. But I would like to improve gas mileage and I don't think misfires will help towards reaching that goal.

So here's what I have been thinking about:
- dirty contact from ignition coil, need to clean them
- bad O2 sensor, needs replacement.

For the rest I can not think of anything else?
Could it be that the misfire is causing the O2 sensor code reading?

Thanks a million for your time guys!

 

I'd go ahead an just replace the wires if it were mine. You don't state how many miles are on it, but if they're original wires, they probably need replacing anyway. As for the O2 sensor, I'd go ahead and get another one. Try to find an original GM one if possible as I've read that some folks have had problems with aftermarket brands, Bosch in particular.

 

I just thought of something else today. The engine temp gauge mostly reaches only 1/4 or between 1/4 and 1/2 of the total range. Is that normal? Could that explain the lower gas mileage? Could it be related to the ses codes?

Thanks

 

Could be you have a bad ETCS and connector. Buy both from a GM ie Chevrolet dealer serving SATURN customers.

 

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Thanks for the ideas guys. I am getting a new oxygen sensor as this is probably the cause for the ses light to come on and go off all the time.

 

Yep -- RjION has the right idea here wrt the ECTS.

 

I had problems with the aftermarket. Try for GM if you can find it. It will probably cost a little more but it might save you some problems.

 

The Chevrolet stealership here wants $50 for the O2 sensor, which I think is cheaper then the part stores. I get the SES light on and my obd2 tester also throws the P0133. I cant feel any difference in the car.

 

Spark plug wires can generally be inspected to determine if they are some how defective. An ohm meter measurement that can be expected is about 10,000 ohms per foot length of the wire and the physical appearance should reflect condition. OR what ever the Saturn Repair book you are using says that they should measure. If the wires look clean and lack any appearance of corrosion or rot they probably are good.
I have not purchased wires from an OEM dealer, ever I guess.
Checking connections are always a good thing to do.
Gas mileage? Dunno what you expect, so dunno what to say except my 94 SL2 automatic gets 34 on the open road and a friends 99 standard shift model would get upwards of 40+. Both satisfactory as far as I am concerned.