clm65

On my way to work this morning, I heard a noise from the front end when I was between 50 and 60 mph. Kind of hard to describe - it was almost like what you would expect if there was a loose piece of sheet metal "fluttering" in the wind. It lasted for maybe 10 seconds and then went away. I have actually heard this same sound several times over the last 5 years. Only about 1-3 times per year, always at about the same speed, and always goes away pretty quick. Could this be associated with the IWE or vacuum system? Something else I should look at? Where should I start?