Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

Should I replace the cat?

Thread Tools
 
Search this Thread
 
Old Oct 4, 2012 | 02:35 PM
  #1  
blueburd's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2012
Posts: 16
Likes: 0
From: Bucks County, PA
Default Should I replace the cat?

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
Reply
Old Oct 4, 2012 | 02:54 PM
  #2  
FiredUpZ28's Avatar
TECH Fanatic
 
Joined: Jun 2006
Posts: 1,285
Likes: 1
From: Elgin, Il
Default

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.
Reply
Old Oct 4, 2012 | 03:03 PM
  #3  
blueburd's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2012
Posts: 16
Likes: 0
From: Bucks County, PA
Default

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?
Reply
Old Oct 4, 2012 | 03:05 PM
  #4  
FiredUpZ28's Avatar
TECH Fanatic
 
Joined: Jun 2006
Posts: 1,285
Likes: 1
From: Elgin, Il
Default

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?
Reply
Old Oct 4, 2012 | 03:10 PM
  #5  
blueburd's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2012
Posts: 16
Likes: 0
From: Bucks County, PA
Default

I don't remember the code but I remember he said it was O2 sensor #2.
Reply
Old Oct 4, 2012 | 03:23 PM
  #6  
baalic's Avatar
TECH Fanatic
iTrader: (8)
 
Joined: Aug 2009
Posts: 1,229
Likes: 12
From: Amarillo
Default

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
Reply
Old Oct 4, 2012 | 03:25 PM
  #7  
blueburd's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2012
Posts: 16
Likes: 0
From: Bucks County, PA
Default

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
Reply
Old Oct 4, 2012 | 03:25 PM
  #8  
VandykeT/A's Avatar
10 Second Club
10 Year Member
 
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
Default

I'm betting on the cat just because of the smell and the crackling noise.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Oct 4, 2012 | 03:33 PM
  #9  
baalic's Avatar
TECH Fanatic
iTrader: (8)
 
Joined: Aug 2009
Posts: 1,229
Likes: 12
From: Amarillo
Default

Originally Posted by blueburd
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 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..
Reply




All times are GMT -5. The time now is 09:29 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE