1992 Honda Accord - Loud Thumping/Knocking Sound

Hi,

Recently after about 15 minutes of highway driving my Accord (F22A1
engine) makes a loud thumping/knocking sound under load. If I shift
into neutral and rev the engine the sound disappears. I took it to the
local Honda dealer and was informed it was more than likely a rod
bearing. There are about 215,000 miles on this vehicle and I have
owned it since new.

Over the past few nights I have dropped the oil pan and bearing cap
assenmly to get at the connecting rod bearings. Using platigage all
clearance show right about .0015, which I believe is within spec, and
only on one bottom bearing do i see just a trace of galling (I have not
inspected the upper bearings as of yet).

Can anyone suggest what might be causing the thumping sounds and what
my next course of action should be?

Many thanks!

Craig