gnojham

Hi all
my wife told me about some issues she is hearing in her car. car has about 110k miles. she is the original owner.
took it for a ride for about an hour.

there is a strange vibration/grumbling noise that occurs randomly. it happened about 10 times during the hour. Seems to happen between 40 and 50 mph and under very light acceleration. It may very well happen under heavier load and different speeds, but i didnt notice it under those other conditions, and most of the driving was at 40-50 mph. made several stops and didnt notice anything from 0-40ish. it did not seem to be RPM related, meaning the noise didnt sound different at different speeds. sounded about the same whether it happened at 40 mph or 50 mph (i realize mph and rpm arent the same thing).
the vibration/noise lasts for about 2-3 seconds, maybe 4 seconds. it seemed to start happening more often as the ride went on. it didnt happen at all for the first 10-15 minutes or so it seems, but toward the end of the ride it would happen every 5 minutes or so, not like clockwork, but in general

i am going to start looking at things today, see if anything is loose, check for codes, etc. but i am no expert. I dont know when i can get the car in to my mechanic.

does any of this sound like a common RDX issue?

thanks for any input