I have an 04 tl that is making a hissing noise under acceleration and feels sluggish. it feels like it wont rev past 4000 rpms..
I already replaced air temp sensor..
Could it be clogged catalytic converters??

any help would be appreciated

 

Do you have a check engine light on?

 

^ +1

Does it idle abnormally? Have you check you hoses? Also if you have a stock intake, check the tubing to see if there are any tears.

 

No check engine light.. it idles rough when could and smells like fuel

 

With the engine at idle, unplug each coil pack separately and listen to the engine. You should notice unplugging each plug makes the car idle worse. If you get to one cylinder that does nothing, find out why.

 

Snakes on a TL??

 

i unplugged each coil every one made the engine idle worse so all cylinders work

 

if you hear a hissing noise it might be a vacuum hose leak

 

i checked i dont see any vacuum hoses that are disconnected

 

it only hisses under acceleration