Cyclo-stationary feature detection for scattered pilot OFDM symbol is accurate detection technique under low signal power. It is, however, problematic that guard interval insertion degrades the cyclo-stationary feature. We have proposed the silent period detection for the compensation of degrading cyclo-stationary. Even if the proposed technique achieved high accurate detection, it sacrifices the loss of guard interval energy. In this paper, we modify the proposed detection technique for cylco-stationary feature detection. For recovering the loss of energy, we propose double stage detector and combining technique. We show the effect of these modifications by computer simulation.