N54 Please Help! Running on 5 cylinders

Hello CTzens wanted to know if you could help me about troubleshooting a problem on my brother’s e90 335i N54. We installed jb4 a few days ago and everything was going well. We were using map 1. Had a few days of strong street pulls. But yesterday while doing a pull at night the jb4 went to map 4 and registered a cylinder 5 misfire. And now the car seems to be running on 5 cylinders. Any ideas? We haven’t checked the coils yet. But it seems strange to me that the car is running on just 5 cylinders. The car has all new spark plugs by the way.