I have an 2003 monte ss pace car 3.8 series 2 with the original mufflers still on it, it still sounds ok?, my question is do mufflers ever go bad ? thinking about putting on some new ones but wondering if I should ? was'nt sure if they ever go bad or get clogged up etc ?

 

The big enemy of any exhaust system is rust. Modern cars tend to use alloys of steel that are far less prone to complete rust through than much older cars. It's not uncommon these days for exhaust to last the whole life of the car - save for folks with higher mileage in areas that salt heavily in the winter. So if your muffler is still muffling, it's still good to go.

Given you've got a 3800, Id be careful swapping exhaust to aftermarket. The 3800 has a 'unique' sound, so a lot of people get in this vicious circle of parts swapping when they go louder trying to make it sound decent again. Lots of videos on youtube that'll give you an idea. IMO if youre happy with the sound now, I wouldnt mess with it.

As for plugging a muffler up - it's not impossible, but it's usually very obvious and caused by a catastrophic failure (cat over temps and sends golf ball + size chunks down the pipe, a braided flex section fails and the flex mesh gets forced down the tube, weld inside a muffler fails and the baffle collapses over the outlet, stuff like that). If it doesnt feel like youre driving with half of the spark plugs unplugged, then you likely dont have any clogging going on. No doubt there's a lot of carbon created by the combustion process, but itll plug up the much smaller passages up around the valves / head / EGR before it would ever have impact on 2"+ piping down the line.

 

I agree with Bumpin', rust is the exhaust killer! My blue Monte still has it's factory mufflers, but it is a 2004 and never saw winter since I bought it in 2008.
As I understand, mufflers just have a series of baffles in them, no elements, no moving parts. As long as nothing is rusted out and loose or a hole in it the muffler resulting in bad sounds, they are good.