Front shock spring spacer?
 

Has anyone else ever seen this?
I just installed my new wheels and encountered this on the driver side shock.
I've been feeling a bump there ever since I had the car. I was waiting to get the new wheels on before taking it to the shop to see what is going on.
Well, I was surprised to find this only on the driver side. I removed it and no more thumps! Drove 3000 miles with it on.
I'm guessing that it was for shipping?

Yup, that's the spring spacer for shipping. Gives about 1" more clearance on the front for loading into the truck. Dealer is supposed to remove them when they receive the car from GM unless they shipped to you. Is the other one in the trunk or glovebox? Might have fallen out if not, but they're handy to have around if you ever need to load the car onto a trailer/flatbed or drive on ramps that don't clear the splitter. Might want to get in touch with the dealer if the other one is missing.

Thanks Alpha 1BC. I do not have the other one. The car was delivered from a dealership to my dealership. It had some miles on it from the original dealership.