Ok guys, I know this is going to sound strange, but bear with me. I bought my 2017 ILX in August 2017. Shortly thereafter, I noticed that whenever I came to a harder stop or took a sharper turn, I could feel something in the lumbar section of the driver seat 'hit' my back. It's as if there's something loose in the seat (hence the gremlin in my title -ha-). Now, I don't feel it all the time, but it's often enough to drive me a bit batty. So, I took the car to the dealer in Charlotte late last year. They had the car almost all day, said they took off the seat cover, etc and could find nothing wrong w/ the seat. I know this isn't my imagination, but I'm not sure what it could be? Could a spring in the seat actually be flexing during a harder stop to the point you could feel it?

I'm at a loss and it seems as if the dealership isn't going to be much help. Any suggestions are appreciated.

 

This is so funny, I have the same issue in my 2.4 ILX 6-Speed Manual. I knew exactly what you were going to say when I read your title.
In my case, it feels like it comes from just right of center on my back, just about mid-way up my back.
Also, I can swear it even makes a little noise as it's happening, like a Snapple bottle cap, but a deeper sound.
It doesn't bother me too much, maybe it's related to the seatbelt tensioners or something.