Just added new BBK Intake and Granitelli MAF about 120 miles ago. Fantastic results untill Sunday. Chk eng light came on upone deceleration, codes p0101b and p0171b. MAF and lean code.
Checked everything all looks good. Light went off on it's own,cleared code drove with diag tool hooked up, fuel pressure, O2 sensors, EVAP sys all ok.
Do I need to re-flash the PCM for the changes made??????

 

You probably need to get it tuned. Lot of hassles you are having for the small gain an intake and maf will give you, particularly without a tune. The problem will probably repeat every so often so find a good shop and have it done right.