Always a good idea to disconnect the battery when installing anything electrical. One, reduces risk, two, resets DME. It's very easy...10mm socket and disconnect negative terminal in the trunk.
First...take logs and see what your trims, AFR, and fuel pressures look like.
Second, swap coil packs and see if the problem follows. If it does, change coil packs, if it doesn't...
Third, swap plugs and see if the problem follows. If it does, new plugs, if it doesn't...
Forth, swap injectors.....
2008 E88--Fuel-It! Stage 3 LPFP & PI--Pure Stage 2 turbos--JB4/MHD--FBO--580whp
2011 E90--Fuel-It! Stage 2 LPFP and PI--Pure Stage 2 Turbo--JB4/Flash--FBO--Currently 540whp/570wtq
2013 Mini JCW--Tune--DP--FMIC--a couple Fuel-It! goodies--265whp/320wtq
2015 F82--JB4--513whp/558wtq. Much more to come!