I have a 2003 TL-S that makes a sort of wheezing or sighing sound after runs of less than 5 miles. I enter garage, go in house, return to garage for something within a few minutes and there is that sound, seems to be in rear area (no jokes please! ). I had air lift shocks in a Lincoln Town Car some years ago and they sometimes made similar sounds when deflating. Any ideas? JC

 

Most likely air escaping from the evap system.

 

I'm sorry, I couldn't help it!