2002 ford mustang v6 jerking engine bucking

2002 Mustang 3.8 Automatic 198,564 Miles Current mods: MAC OffRoad H-Pipe, K&N CAI, MSD Wires I got a code for misfire on cylinder 5 (P0305) a month after rebuilding the upper end of the engine (had a blown head gasket). The car ran extremely smooth and got great gas mileage before the problem...

What's up guys, My problem with my 02 Mustang is that every time after like 30-60 minutes of non stop driving, it starts to buck and jerk. The best way to describe it is if it's being choked. When starting from a cold start, it'll run fine with no trouble. Only when it has been driving for a...