hi i have a 974x4 ls v6 zr2 blazer and was wondering why when i rev my vehicle a bit sometimes it rattles underneath..the check engine light came on after i got it back from a shop that put a new used engine in it from a 95 i think..and i called them with the codes it read which i forget now and he said it was because the catylic converter was getting to much air could this be right? do i need a new catylitic converter? ..it sounds sluggish also when i rev it up almost like it has an exaust leak underneath but i don't see any fumes coming from under ther i have a 2.5" glasspack that i got for a toranado a while back but thinking about putting it on my blazer in place of the muffler do i need a new cat also or can i use the same?

 

classic signs of a plugged cat.
poower throttle response, SES light, bogging down, and rattle.

a new cat is in the cards for you. you may want to consider a new O2 sensor while you are there if it is throwing that code also as it may have been smoked by what the cat was feeding it. bad plugged or melted cats can take down all of their down stream pals (02's, muffler, etc) on their way out. one last F-U to your wallet as they die. swap it out, the sooner the better.

i would suggest a universal as it will be less expensive than the OEM replacement and work just as well.

 

k thx. a local exaust guy said he would eliminate the cat and run a pipe there and add on my glasspack for 60.00.. sound good?

 

You can't eliminate the cat. If you do you will be treated to the warm glow of the Check Engine light. The fore and aft O2 sensors check cat converter operation and will not see that the converter is doing its job. Just replace it and be done with it. Also it won't run properly either.

 

besides what 96Blazernut said, you need your cat for emission testing. 'cause there ain't a snowball's chance in hell of it passing otherwise.

 

not to mention a cat delete on your year is a federal offense

 

it's not year applicable. if it was on there from the factory, then it's illegal to remove it.

 

which is why his year would make it a no no

there are tree hugging hippies in say California who have catted out their sweet classics for a greenier (read as douche-ier) state. that being said, you could hack it off all day... that's what i meant

this is from catalyticconverter.org:
Rules for Replacing Converters
In 1986, the U.S. Environmental Protection Agency issued new guidelines for the construction, efficiency and installation of aftermarket catalytic converters. All CleanAir converters listed in this catalog have been designed, tested and manufactured to meet this policy.

In addition, CleanAir converter listed in this catalog is appropriate for use under the current requirements of the California Air Resources Board (C.A.R.B.).
E.P.A. guidelines state that replacement converters may be installed only in the following situations:

1. The vehicle is missing a converter
2. A state or local inspection program has determined that the existing converter needs replacement
3. Vehicles manufactured prior to 1996 must have more than 50,000 miles, and a legitimate need for replacement must be established and documented
4. In cases of OBD Il-equipped vehicles (1996 and later), the O.E. manufacturer's 8-year/80,000-mile warranty must have expired and a legitimate need for replacement must be established and documented.
Please note that Federal law prohibits removal or replacement of a properly functioning O.E. converter.

so the year does play a factor in things, just not the OP things

 

just stick a drill bit down the cat to get all the foam and finemetals out of it then put it back on, looks legal and still has the o2 sensors...thats what was done to mine

 

Why do you care so much? Are you a cop!? HE'S WEARIN' A WIRE!!!
/\ Just a joke!

On a serious note, by the constitution, the federal government can't mandate a catalytic converter. So, it's not a federal offense, it's absolutely illegal to mandate them and people will do whatever they want. Especially that law that says you can't replace a working converter with another working converter. The framers are rolling in their graves!

Oh, and you can pass emissions cat-less if you fool the downstream O2 sensor if your state just checks for codes. But you didn't hear it from me.

Regards,

Thomas