My gf has a 99 Bonne, SE, Series II. Her check engine light has been on since before we met. She finally went to Autozone to get her codes pulled and those are the 2 that she got. Now, I have already changed the spark plugs because I read sometimes this could clear one of those. Other than that, I havent done anything to the car. Any suggestions/tips would be appreciated as her inspection is due and we need to resolve the engine light prior. Thanks guys!

DTC P0141 HO2S Heater Performance Sensor 2
and P0300 Random multiple misfire.

When referencing a code, please list the name. It helps us by not sending us out of the thread to know what the code is for.

I'd start by clearing the codes and seeing what comes back. If the O2 sensor comes back, it'* the rear O2 behind the catalytic. If the P0300 comes back, check the coils and wires.

Sorry for not postin the entire codes. Note to self for next time. And I too was thinking it was her O2'*. She has 150k on her car, and figured those hadnt been touched since the car was put together. I'll attempt to swap them out this weekend and will let you guys know if that helps or not (hopes it does for her sake). Thanks!!!

Uh...don't do that.

O2 sensors ... only the rear one tossed a code. That one only tells the pcm if the catalytic is working correctly. It has nothing to do iwth how the car runs./drives.

If you want, change the rear. I'd clear the code and see if it'* an old code though.

Dont do what? I wasnt going to do all the O2 sensors, just the ones behind the cat like you stated it was from. I know on my f150, to clear the codes, I unconnect the battery for a few and then that clears it. Is this the same for the Bonne'* or is there another trick? Thanks again!!!

Oh..ok. You said sensors, plural. Being a truck guy..I understand why... you got two on the truck. I figured you meant both the front and rear sensor as the car only has the two.

Unhooking to clear the memory should work.