Hey guys,
Done similar thing with my x5 n55. Mainly upgrade stock intake system with aFe Power Magnum force stage 2 intake.
Result is shitty without tune
Car start idling rough at cold start. Some time it even shut the engine off. Now waiting for tuner to adjust and calibrate amount of air going through upgraded system. Hope it will solve the issue.
I’m on MHD Stage 2+ with VRSF FMIC, Charge Pipe, CattLess DP. Nothing was caused any problem before, but that Intake makes me nervous. Also waiting for RP Coil Kit to arrive.
If it helps you, based on my experience I suggest find appropriate tuner and consult before messing with MAF sensor.