This paper proposes a trust-based, fuzzy-integrated particle swarm optimization (fuzzy-FPSO) system for intrusion detection and prevention in mobile ad hoc networks (MANETs), aimed at securing routing. The system identifies intruders based on trust values and optimizes path selection to ensure secure communication, demonstrating superior performance in various attack scenarios. Evaluation results indicate significant improvements in throughput, delay, detection rate, and routing overhead compared to traditional methods.