not really sure how to exactly describe the noise but...all of a sudden it started doing this last night when i had to go somewhere. when i start up leave it in P and let it idle, the car makes a bogging/vibration noise. It also does this when put into D with rpms around 200-600 and when im accelerating to 1k it still makes the noise but when driving past 25 mph it doesn't do it anymore. on the muffler it looks like there is a hole starting to form. when my dad took it to the mechanic to get the alternator replaced, they checked under the car and said that the muffler and pipes have to be replaced in the near future because there are some sections that are starting to rott. just want some advice and just to make sure that the noise/bogging is actually the muffler and nothing else.

 

I'm pretty sure that unless you have large holes in your exhaust system you won’t hear much other than the sound of a crappy exhaust. I have an open y-pipe thanks to my broken flex pipe* and only now do I get a lot of vibration from the exhaust sound shock waves, but it also runs faster too.

The bogging IMO cannot be related to your muffler hole.


*pic if you are wondering.

 

could it be bad plugs?