So I noticed that my car has progressively begun to get slower and run crappier everyday. I had an 02 sensor code not to long ago but when I accelerate I hear a crackling noise coming from the cat. When it idles it starts to shake and sway from side to side in park and smells like rotten eggs.I also get around 12 mpg in my v6 firebird so its making me think its the cat. Should I go ahead and buy a magnaflow?I doubt the 02 sensor would cause the car to run like that.Thanks

 

Yes it will. Replace the 02 sensor. Having said that, I had a broken up cat in my '00 V6 and replaced it with a 3" Magnaflow and never had any issues. But if you have an 02 code I'd check the wiring and replace the sensor. Its the cat that WONT make the car run like poo.

Also, I'd run some injector cleaner through the fuel system (not through the vacuum lines, through the actual fuel rail/injectors). And it also wouldn't hurt to clean out the throttle body and mass air flow sensor as well. Its not that important to clean the throttle blade itself as it is where the blade meets the bore. Your car is drive by wire which means it has no idle air control valve - it just moves the throttle blade to adjust idle, so if its all gummed up with carbon it won't idle very well and may start then just die out - then start right up again.

 

Thanks man, should I be safe and replace both while Im at it or just do the 02 sensor?Is there a certain sensor or brand I need to get?

 

Well if you only have a bank 1 OR 2 codes you can just replace that one - but if you have the cash I'd do both, since they are likely the same age. I've had Bosch, Denso, and parts store brands cause funky 02 heater circuit codes (check engine light came on). Never had an issue with a factory Delco sensor. PLUS - 02 sensors usually start failing "rich" without causing codes, so that very well may be your MPG issue.

Do you remember the actual code?

 

I don't remember the code but I remember he said it was O2 sensor #2.

 

I just got done hunting gremlins in my 3.8, i would check MAF, and change Cat, those 2 things alone made my car feel like i gained 50 hp......no joke

 

Thanks for the help guys. Ive done the TB cleaner and MAF cleaner along with fuel treatment so once I get the cat and sensor I should be good

 

I'm betting on the cat just because of the smell and the crackling noise.

 

I cleaned mine too but it didnt fix it, i used an online coupon code and got like 50$ off a new one non refurb so i just replaced it. I challange it against any other stock 3.8 camaros/birds now for mpg and 1/4 times..