how are you testing for spark ? HAve you cheked the Coil and Ignitor them selves. also check all the wireing in the plug and trace it bck to the Main harness and further to the ECM. Check for Stored DTC's in the ECM see if there is any error codes there. When did this start and what were you doing ? also i believe there is a fuse on the preludes for the ognition system.