Stock muffler life expectancy
 

This afternoon I thought I'd unbolt my muffler from the exhaust system to see if it would help smooth out my rough idle. Well, it did. How long should a stock muffler last on these vehicles? I didn't see any burn through marks on the muffler just what I would consider normal wear and tear (i.e., typical surface rust in some spots).

Oh, and I know it's stock because it has a manufactured date of 1997 stamped into the shell.

I never had a factory muffler go less than 100k.

my 1999 blazer muffler went 114,000 miles had to replace it because it got crush by a log in tall grass I did see hunting. but inspection after removal no excessive rust and was quieter than the new one prior to the crushing part.
the new one is a walker muffler I guess they are good ones but not as quiet as the original one.

+1, usually they will rust off accidently get crushed before they go bad.

everything on my blazer was factory. even the shocks and it has 186k on it. so of course iv threw new parts on it. but mine dosent idle rough or nothing. so i guess i just got lucky

My family had a 1995 Jimmy that was 100% stock. We sold it at 192k miles and, outside of the typical surface rust, the muffler was completely fine.

my stock cat, and muffler lasted to 120,000 miles. then the cat shattered and clogged the muffler

My muffler and cat are still running strong at 123k

My 04 has 188k on the original muffler and cat. I have been considering a new cat, but the muffler looks fine.

I have 121k and while mine has rust on the back of the muffler, both the cat and muffler are still fine and are original.

188k original cat and muffler
 

On mine they were both bad,the cat was completely burned out and the muffler is rusted through in places.Since i live in the rust belt no surprise.I like the way the 4.3 sounds with a standard turbo muffler not loud but no too quiet either.

GM 90* engines sound good with turbo mufflers on them. I have one on my 99 v6 Camaro.

Let's see, stainless steel exhaust system, no salt in the winters, 12+ years old, 220K miles and mine is just fine. There is a rattle do to a tweaked system that doesn't align up just right with the hangers from some long forgotten offroad adventure that is now held in place with some stainless steel wiring, but other than that?

Still plenty of miles to go, IMHO. And yes, still the stock system as I bought mine new in 2000.