Can't offer specific sensor info but being a long time motor head , if the oil pressure is dangerously low , the engines main reciprocating parts will "rattle" when warm at or around idle . Like when you first start it cold before oil pressure builds .
If this is not happening , I would suggest a sensor related problem .

I really dislike the cold startup RPM level of my 06 coupe which I consider to be in excellent condition . It quickly dies down in seconds but that first burst of non pressurized high RPM rattle is NOT a good thing , but I don't know how to adjust it yet so I'm not going to play with it . I know it is supposedly an emission help to cold cats so they heat up quicker & is utilized on most vehicles now days .