Come out of work just like any other day and fire up the TL. WTH!!!! who modified my exhaust system while I was at work???? The car sounds absolutely strange. For years it has sounded exactly how it was modified to sound, how I liked it. HFC, no mid, longer resonator to stock rear mufflers with quad tips.

Now it sounds completely different!!! No CEL, engine runs fine and smooth, no perceived power loss or drivability issues, although I only drove 3 miles home so we will see. Perhaps HFC disintegrated? would expect a CEL.

Not really sure how to diagnose. not sure what it would have sounded straight piped so if I remove at j-pipe not sure what it should sound like?

Its not louder, its just way different and not in a good way.

Strangest thing ever.

 

did you have a long day at work

 

by hfc you mean the 3rd cat one right? not the hfpc. if anything happened to that cat, it would not cause cel because there are no sensors in that one

most likely reason is maybe you scraped the exhaust somewhere and now have a leak.

 

No scrapes or dents or leaks. All three are high flow cats. Sound out of the tailpipe is different. Hard to describe. Wife says its not as crisp. More muffled but not louder. I noticed the rpms dont drop the same and it doesnt "gurgle" like it did before when off the gas. WTF???

 

Odd...in for the reason

 

get the car up in the air and check under your car to see if all exhaust parts are intact? Most notably the 3rd cat. It's pretty common for thieves to steal cats to scrap for $$

 

everything is intact

 

Maybe post up a video?

 

^+1

 

I'm pretty sure he'd know it if someone stole his third cat.

 

I know you said everything was intact but did you check the mufflers for holes, scrapes, etc..

 

lol yea agreed....dont think that would slip under the radar

 

Make sure no one stuck a potato in your tailpipe.

At idle, do you see any fluctuation in RPM?

Get her up to temp.. do some hot runs.. and get a IR therm and snap some temps of the CATs going in and out.

 

Disconnect the battery for a bit and see if it changes?

 

Sounds like you had the inside of a cat break. It happened to me and my car ran like crap and sounded way different. It would do it as the cat cooled down and then maybe cracked and broke all together. Check your cats

 

 

will investigate. sounds like a good reason to swap j-pipes and see what I find

 

Tap the cats with a hammer or something and see if it's a thud or a ringing/hollow sound. What type of resonator do you have and how long ago did you add it? Some people say Magnaflows and the likes get louder over time as the packing packs itself in over time.

 

Problem found and solved! Once on a lift it was apparent that one of the forward hangers tore off and left a bit of a hole! Could not see it without the lift! Procats still intact after 6 years.

 

Good to hear you figured it out.

 

too much stress at work??

 

Maybe the carbon built up?