most dealers will do a once over for a vehicle before warranty expires. It's in their interest too since it can potentially generate addl revenue...
That being said, I'd throw 'em a bone and have them do and O&F change at the same time requesting a final warranty inspection. Toss in (and get them to write it on the service invoice) 'customer notes car making odd rattle sound in engine compartment' & 'customer states vehicle seems to exhibit odd behavior when driving'. This way, all your bases are covered
How many miles are on it? Assume you're running out of warranty due to time? FWIW, and I'm sure some resident expect will prove otherwise, I haven't heard of any IMS related issues w/ late '06 or newer motors. Keep driving and enjoying your car!
Good luck
