I have a 99 S10 Blazer with a 40 series flowmaster muffler on it. Recently, sometimes when i accelerate my acceleration is very bad and seems like there might be a lot of backpressure in the muffler, im not sure what else this could be. It makes a weird sound from the exhaust when it does this. Any help would be great, thanks!

 

Your catalytic converter may be plugging up... they do this, and when it does it makes a god awful noise... when it gets really bad your vehicle will actually sputter like an old cartoon car lmao.

 

x2 on checking the cat. The broken insides can migrate to the muffler and clog it.

 

Thanks for the reply! Do you recommend to get a new cat or is there any easy way to repair? Should i do anything to the muffler since you said it may affect the muffler too. Thanks again!!!!

 

pieces from the cat can clog the muffler aswell. it is your call on the muffler change. i would remove the 02 sensor pre cat an see if it runs any better if so your cat is probably clogged. if you leave it to long yes you will need a new muffler too

 

Do you notice a weird smell when you're driving or after you get out of the truck from driving it? If yes, then congrats, your cat is bad. If its a fairly recent problem you can get a universal one from Magnaflow for under $75. The one I put on my Firebird worked well... until I blew the valve seals. Now its clogged like hell.

 

Well i got the new cat and it seemed fine but sometimes on the highway i would have the cruise on 60 and exhaust would sound different and rpms would fluctuate from 1900 to 2200. I am wondering if some stuff from the bad cat is in my muffler. The guy that installed the cat said if there was something it would just come out, any ideas? Thanks!!!!!!!!!!!

 

flows suck, get a better muffler.

 

Thanks for your opinion but i am still wondering if anybody has any suggestions to my problem. I dont know how to check if something might be in the muffler or if the stuff that is causing it might eventually come out?

 

The internal design of the 40 series shouldn't allow for too much stuff to collect in the muffler. If you wanted to be sure, you could pull the muffler and shake it around.

But your problem sounds more like an intermittent electrical problem causing your engine to run differently/poorly.