I have a 2006 DTS, but this probably applies to many other models.

The big plastic shield under the front end that attaches with about 15 plastic retainers has come loose in one area at the front edge. I replaced some of the missing fasteners to put it back in position. Yesterday on a day-long 700 mile drive I heard it dragging on road dips. Got out and saw that it had dropped down again and was now scraping the road at speeds over 60 mph. Before I make my return trip home I need to do something about it.

Question - how necessary is this? I assume it is there to smooth air flow under the car to improve fuel economy. Yes? No?

If just for fuel economy, it is getting removed.

The only other function I can think of is to protect undercarriage components from road debris, but many other vehicles do just fine without that kind of protection.

Thanks for your help.

 

It's primary function is to aid in cooling and a/c performance. The shield forces air through the radiator and not allow it to escape under car. If it's missing in certain climates could lead to increased operating temperature and decreased a/c cooling. The little rubber deflector is not as important.