My lady and I drove from Richmond, VA to Sanibel Island, FL only to hear a weird, loud engine noise that is not tied to engine speed when we reached Fort Myers. Sounds kind of like grinding marbles in a can. Very loud at idle but hard to hear when driving. The CRV has 138,000 miles on it with pretty decent preventative maintenance. I made a Monday am appointment at Honda of Fort Myers, but would love to get some ideas as to what this might be. HELP!!!!!