2003 MERCEDES CLK 430 CRACKLING NOISE!!!!

MY RIDE HAS JUST STARTED MAKING THIS CRACKLING NOISE. IT DOES IT IN FORWARD OR REVERSE BUT ITS NOT CASSISTANT WITH THE GAS PEDAL OR LACK IN POWER. its very irratating!!!!!!! IM THINKING CATALYSTIC CONVERTOR BUT NOT SURE IF U CAN HELP EMAIL ME [email protected] (DEREK) tyvm