I've been having an intermittent thumping/clicking/jackhammer sound when I accelerate at speeds over about 60 mph. It only happens when I am accelerating; when I let go of the gas pedal the sound stops immediately. It sounds like something is knocking on the wheels, and I can feel the thumping through the gas pedal. Actually, when it gets really hard I can feel it throughout the car.
I've read some of the other forums, and it sounds just like this one: http://www.honda-tech.com/showthread.php?t=1534926
But I don't see how it could be unbalanced tires; my steering wheel doesn't shake. The CV boots are still intact. Could this be the wheel bearings, or is it most likely an axle problem?
I'm actually on the road going from Kansas to NJ, and it's gotten worse along the way. I already stopped once for a mechanic to look at it and the axle & joints looked solid enough. He wasn't able to reproduce the problem because it seems like the knocking/thumping only begins after the cars been traveling at 60+ mph for about 30-60 minutes. Perhaps after all the parts warm up? Unfortunately since then, the knocking is getting louder and harder, and when it gets bad there's a lateral shaking as well.
Needless to say, I've stopped for the night and will be bringing it into some nearby garage tomorrow. If anyone could recommend a garage near Richmond, Indiana, that would be great too.