The growth of laptops, Personal Digital Assistant (PDA) and 802.11/Wi-Fi wireless networking have made Mobile Ad-hoc Network (MANET) a popular research topic recently. Therefore, with more attention on MANETs lately, the security issues become more important and urgent for managing and deploying in such networks. The flexible deployment nature and the lake of fixed infrastructure make MANETs suffer from varieties of security attacks. In this paper, we propose the Misleading Routing Attack (MIRA), which is different from the well known gray/black hole attacks, in which a node is relaying the coming packets and not dropping them, so its neighbors will not report this node as malicious, since they will sense that this node is relaying the packets and not dropping them. This proposed attack aims to delay the packet as much as possible so as to let the source node timeout before it receives the ACK. Also it aims to overload the network by increasing the number of unexpected routing packets generated in the network. Our simulation results show that the existence of an adversary in the network launching a MIRA will degrade packet transmissions in the network as well as increasing the number of lost packets.