gtv237 wrote:Totally normal. It's the EVAP system testing itself.

Good to know, thanks. I was about to dismantle the under carriage and look for a gps tracking device

Chiadog wrote:I think your car is infested with a nest of Vibe Vipers! Or more likely this: Purge pump.
https://www.youtube.com/watch?v=9EREwCYvX5c

Thanks for the info! Did a lot of searching over the interwebs and nothing. "Purge pump" was the keyword I needed.

Is this normal? I always hear this hissing noise underneath the rear of my bumper somewhere by the muffler while the car is parked, engine off. This usually happens approximately 5 hours after I have parked in the garage where it is quiet. The hissing sound lasts about a minute then shuts off. Is th...