need help to diagnose a noise where to start looking

[96tsimom]

I appologize in advance hope to just get some ideas of where to start- i have a 96 tsi awd a/t. I have a noise that is a low rumble type of noise. it is only heard when car is still at idle or at a stop. It goes away when you are driving. It is best heard from drivers side and you can feel a vibration from in car from the passenger side back seat. have been under the car and have not felt anything loose. the driveability is not affected it steers and runs fine. Has anyone else had this problem? Anyone know where I can start in the diagnosis? Thanks in advance to anyone for any suggestions.

 

[ddavisaf]

Does the amount of gas affect the noise at all?
When at idle if you rev the motor does the sound go away or get louder?

 

[96tsimom]

Sorry went out to check. Doesnot get louder when step onthe gas stays about the same occasionally sounds softer and goes away and when you let off the gas it comes back there is an obvious smell of fuel and no cel in case you ask. O2 sesor upstream just changed but the sound was there before that- had cel and logger told me O2 sensor.

 

[ddavisaf]

You don't have a downstream o2 anymore right?
You did the downstream o2 bypass mod I'm assuming?
I'm wondering if your exhaust gasket is shot..... 3" catback, when you got it put on you didn't reuse the old gasket right?

 

[96tsimom]

Still have downtream O2 sensor. New exhaust gasket as it is a new 3" turboback with high flow car. It could be an exhaust leak but much further back it is a slip fit exhaust and has hangars bolted together on it . It is an aluminized stainless and a pia to take the hangars off. Does anyone know if it could be or maybe should be welded? We fixed the one leak up by O2 housing caused by someone trying to remove the exhaust at the hospital where I work- security scared them off. Don"t drive the car to work anymore. But I guess Ill look at the exhaust first and then go from there. All the hangars are tight.

 

[96tsimom]

Still have downtream O2 sensor. New exhaust gasket as it is a new 3" turboback with high flow car. It could be an exhaust leak but much further back it is a slip fit exhaust and has hangars bolted together on it . It is an aluminized stainless and a pia to take the hangars off. Does anyone know if it could be or maybe should be welded? We fixed the one leak up by O2 housing caused by someone trying to remove the exhaust at the hospital where I work- security scared them off. Don"t drive the car to work anymore. But I guess Ill look at the exhaust first and then go from there. All the hangars are tight.

 

[ddavisaf]

Weld away
Those hangers may be tight but they don't always seal up like a good welding would

Sorry to hear about someone try to actually steal the exhaust off your car. I think that's the first time I've ever heard of someone doing that. Everything else yeah, but exhaust? *shrug* People......... WTF