Having some issues with my 02 f4i, wants to bog low end but as soon as I give it some throttle above 5k it works perfectly fine. Idle is kind of weird. I’m thinking ignition coils espically after replacing plugs last week. Can anyone give me some ideas??

 

Cylinder 4 misfiring will cause the bog.
Ideas are: vaccum leak, fuel/fuel pressure regulator, valves out of spec, ignition coil[s].