Tom, never happened to me but if the radio was replaced and it did not remedy the problem, it sounds like a possible electrical lead to the radio may be the cause. Have the dealer test it with you on a test drive and perhaps they can locate a faulty wire or connection. Also, try to observe the radio at the time it happens to see if it is related to losing the music or the power to the unit. This will help narrow the fault between a lead to the unit or a lead to the speaker or amplifier.
Let us know what happens.
