loosecannon affirmative. After heat and beat that was exactly what needed to be adjusted.sounds like oscillation.
i am wondering if someone cranked the bias pots on the driver and final.
try setting the bias on the driver and finals using these instructions: http://www.cbtricks.com/radios/galaxy/dx99v/dx99v_trans_adj.htm
when they say to remove the "metering jumper" they are referring to the little PC board sitting vertically in front of the driver and finals.
just a guess.
LC