CEL came on. by the descrip of the list of probable causes, it seems like it leads to the 02 sensor up front? i've noticed a decline in my MPG's since the light came on as well. 4c 2.2l 125k miles. the drop in MPG's is probably in part of the sub zero temps that we've had in IA for what seems like forever now. the car starts fine and isn't rough when driving or idling. i'll probably run some Seafoam though the gas tank. guy I work with is changing my o2 sensor for me this weekend. Assuming i'm right here (please tell me if i'm wrong about the 02 sensor), which sensor do you guys recommend getting? I've got advanced auto and o'rileys local.

More than likely the first HO² is at it's end, stick with OEM or ACDelco and avoid Bosch. When your first HO² goes bad so does your MPG because when light is on engine remains in open loop. Cold weather doesn't help. Did you clear the codeto see if it would come back?

the guy at o'rileys couldn't get the code to clear(is that bad?) but he ran it twice and that's the code that came up twice. i was told to buy an 02 sensor /w the connectors, not the one that you have to splice the wires. (don't go cheap! he says)

That's right, plug&play. Was the engine running when he tried to clear it? If the car wasn't running the code should clear unless he didn't quite know what he was doing.

the engine was off. maybe i just need an 02 sensor that bad it wouldn't clear? =)

It should clear, never had a case where a "P"code wouldn't clear, except SRS codes but those are "B"s.

I got a denso 234 4342. Is that going to be okay?

Should work....

Thank you very much. You have been very helpful.