99 V6 mysterious exhaust leak & gas tank issue

[Chigga]

Hey all, my wife's 99 V6 is driving me nuts with the exhaust leak.

I was able to take a thorough look in the engine bay and under neath the car but still wasn't able to pin point the problem and hope that your experience will be able to make the right solution.

it is an incredibly loud exhaust leak, especially cold, it make the car sound extremely ghetto and if its in stand still traffic, you can smell the exhaust inside the car, I can't find any crack or any blow by in the engine bay, and the pipings look fine to the eyes and can't detect any leaks.

the check engine light isn't on, so I don't think its before the O2 sensor, but then again, I've been wrong a lot of times before.

where can the leak be coming from? its the loudest close to the firewall area.

another thing, it taking forever to fill up the car at the gas station, I think its the vent valve, I searched and can't find much info on it, the line is not obstructed by anything, any good way to find out which part need to be replaced?

thx in advance for any help.

[chronoti]

break in the flex pipe

[csaxon]

The usual suspect is the flex pipe.

[Nervous]

Heh, a very familiar picture

[73sport]

The EGR tube up to the intake has been known to crack too.

When the car starts the ECM runs a different fuel curve until the O2 sensors come on line. That might explain the noise difference plus the idle is higher when cold. Notice the cold start RPM and match it later by adding throttle. Is it just as loud?

Other than that, the tube being broken, well when the engine warms up, more of the gases actually go through the EGR pipe and theres a slim chance that could make it quieter but I doubt it.