[wmjosiah]

Update: Decided to drive the car to DC and back (from MA) anyway as I'd been planning on that trip for a long time. The car was a joy to drive and performed admirably. It runs perfectly, threw no codes, but still makes that alarming noise sometimes under the conditions previously described, though it's doing it less and less often and less loudly as time goes on, it seems. I'm sure I need to pull it apart to fix it, but it doesn't seem to be affecting the performance or gas mileage of the motor in any way.