I have a 04 supercharged monte carlo i put on a slp pulley and a slp cold air intake i also changed my mufflers last feb. Now my car is burning up cats im on my 3rd cat had 4 diagnostics they say i need a gm cat that cost $600 if anyone has any idea im runnin out of them i really need help

 

how many miles do you have on your monte? I thought there was a 100,000 mile guarantee on cat converters?

 

Get a new downpipe. Do you have emmsions testing, if not get a catless one.

 

No its 80,000 and thats about when the first one burnt up NOW I HAVE 88,600

 

A new down pipe? Will that solve the problem we do have emissions but i have spent so much money on this problem i really need a solution that will work so if ur sure just reply

 

I have an 05 MC SC with the same issue. My solution was as follows:

I have the larger downpipe
I had muffler shop install a removable bolt up cat that can be removed and replaced with a straight pipe and an O2 sim. I am in California so our smog test is once every 2 years. a few days before my smog I bolt up the cat, get it smog tested, then reinstall the straight pipe. Problem solved.

 

https://www.zzperformance.com/grand_...=551&catid=110

Get a 3 inch since you are supercharged.

Problems solved