I am having issues with my 2003 Monte Carlo SS. The Catalytic converter is clogging but I am not getting any codes associated with it. I was getting a code for the EVAP system (P0440). I replaced the Purge Solenoid and Vent Solenoid. I'm not sure if I have the EVAP problem fixed but can that cause the converter to fowl? The car is running tip-top, it's not missing, it's not burning oil out the exhaust, it runs smooth and the fuel pressure is good.

What else may be causing the converter to plug and can I straight pipe the converter?

 

i got a question... with out throwi?g a cat code or anything how do you know it's getting clogged

 

The only (good) way to replace your cat converter.

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

 

I was not getting any other fault codes besides the EVAP. I was experiencing a huge loss of power and mileage to the point that it was difficult to even get to speed. I researched it and suspected it was the converter. swapped out the converter and got all my power back and then some. The car had more power than I had ever experienced, even when it was new. I thought the EVAP problem may have been the culprit but this converter is clogging to.

Could it possibly be a bad O2 sensor. I am not getting any codes for the converter or for the sensors but the car does have 150,000 miles. Is it possible that an O2 sensor can go bad without throwing a code and also cause the converter to clog?

 

How many miles are on the car? How many miles before the new one started cloggin?

 

total 150,000, replaced the first one a month ago, i have 2000 miles on this one and it is starting to clog.

 

get a high flow they only run about 200 and see if the last place to install it will warranty the second one.

 

I am having the same problem i have 96000 miles on mine, engine light came on code wasP1404 replaced EGR valve ran a little smoother, but has no power still. Master flo system was cleaned, one sensor was tested, little restriction, but not bad... any other suggestions?

 

the word on the street is that the stock intake manifold is made out of cheap plastic and thus tends to crack and bow, which causes coolant to enter the exhaust system and collect in the catalytic converter which will clog up your exhaust pretty quick. i have the 3.8L SS with 108000 miles and i always get decent acceleration from a cold start but once i get 2 blocks away the engine starts choking and struggling and can't even top 3000 RPM... i am pretty sure this is the cause, but i won't know for sure until this weekend

 

Will running that cat throw any codes or cause any troubles with running it on a non tuned car? Cuz I do not have a tuned pcm.