under front bumper/engine shield
 

2012 camry, this shield goes back about 2 feet & it is clattering on a lot of stuff. It goes all the way across the front. I'm wondering if I need to leave it on for what reason.

If it is making noise or rattling around, you should check how loose it is and if you need to tighten things up or get new fasteners.
Ultimately, you do not need it. It does help with aerodynamics and fuel efficiency. It is there for a reason.

the problem is that there is a lot of play in it, up & down being flimsy. It is hitting on stuff mainly along the front-not being enough clearance. I stuck 5 small chunks of foam up under on top of shield along front. just hope it doesnt bother any sensors or melt.

Let us know if that works. You could buys a new panel or try spacers where the screws are. A lot of people just scrap them when they can't get them to fit right.

critters
 

cat fight under car last night, only one chunk fell out. Pretty good hehe. It's still too early to tell. Is quieter. I like that.

Quieter is good! Let us know how it goes! And, good luck!

I have the same issue with my 2010 Camry - local Pep Boys just zip tied the things back on. Can the car do without them in California? (you know how regulation happy Sacto is)

I solved the noise problems I was having by tightening the 4 bolts under the front bumper that snug up the shield, now 10 months later the noise is back, stripped a bolt trying to tighten again-last time had to get very tight to quiet it down. Now there telling me there are plastic grommets up there that the bolts screw into. How to replace?

Most likely push into the sheet metal as show in the link below.

https://www.google.com/search?client...screw+grommets

That link doesn't show anything but the parts, I have the part. Do not know how to get one out to replace it.