Little Green

ok so I am idling at a light and I hear a rumbling coming out of the back of the car. I think it's a diesel truck or something behind me. Noise goes away. I park the car for an hour. Go back out to grab some coffee and I hear the noise again but now it's constant. Loud rumbling. Goes up and down though not necessarily with the rpm. Even shut the car off and the noise continues for 15 or so seconds. Sounds like something wrong with the exhaust. While parking the car the idle jumps up 1200 or so rpm without my foot on the gas. Gurgling/rumbling sound. Not a good weekend not to have my truck. Raining hard and hit one puddle but not terribly deep and a puddle I have gone over 100 times before. Freaking me out. Any ideas. 06 S

awryexperiment

Any possibility that some water got in the tail pipe? Maybe a few fish to complete the ensemble?

If its water, it could be boiling and causing the noise. Do you hear any sloshing when you shake the exhaust? Do you have strong lungs?... maybe if we gave you a long straw....

I also think the observed RPM jump is a red-herring (maybe pun intended).

s4for5

You have 2, both sides under rear seat bottoms are access panels into tank.
I would tilt up the bottom cushions and listen for the noises there.
Perhaps climb back there and have someone drive you around a bit, might help isolate the noise area a bit further.
Good Luck

Little Green

I was so worried I just showed at the dealerhsip this AM. Very accomodating. Took my car in and discovered that one of the sunroof drains must be loose which has allowed water to inundate the box where the subwoofer goes. This in turn created a ton of noise until the subwoofer fried. No noise this morning. They removed the subwoofer, sucked the water out, ordered a new sub and drain pipes and scheduled me for service with a panamera loaner(my usual loaner). Car runs fine and no more funny noise. Mad props to my dealership for taking the time to take care of me with a smile and a cup of coffee with no appointment. (Porsche of the Main Line)

awryexperiment

Glad to hear you were treated well!

So was the rumbling sound coming from the subwoofer?? even after the car was off?

Slow Guy

I'm not the least bit embarrassed to say I never would have guessed that one......

Little Green

I said the same thing and apparently there is still a connection to the radio for about 10 seconds after the car is turned off. Never would have thought a speaker issue but they removed the sub and the noise is gone.