m issfire after nitrous install

[03mach1ne]

I've been trying to figure out what is causing this misfire on cylender 5 i believe. There is a wire that i think the guys that installed my nitrous put in that tins from cylender 5 coil pack and the other side goes into the fire wall where all the other wires for the nitrous enters the firewall. If I hold the wire in a certain position the misfire will go away but always comes back. Any ideas on what this wire is going to? I've already chnged coil packs and spark plugs.