A simple but effective inter-radar interference mitigation solution for automotive FMCW radars is to detect and suppress the interference in time-domain by taking advantage of the signal level difference between the interference and desired beat signals. However, interference detection and SNR improvement fail, if the number of interference radars is large for example, thus it is a challenge to appropriately control the interference detection threshold from the received beat signals including both desired and interference signals. This paper proposes an advanced wideband interference suppression technique using envelope detection and sorting for automotive FMCW radar. Furthermore, this paper evaluates SNR improvement in various inter-radar interference environments by computer simulations to validate the proposed technique.