I don't think that cleaning MAP sensors will help. May be, only for cars with low mileage. They cost about 150$ both, so it's better to change tjem and be sure that this system is completely OK.

Detroit tuned manual says that it's necessary to reset ECU after installing BPV. Don't forget about it.
My valve isn't installed yet, but many friends use such BPV without any problems

 

just installed it and wow even the flat spot before 3k rpm is gone.

 

Glad to hear it all worked out. Whick sensor was it - upstream is my bet.......

 

I had a faulty heat sensor and that thing would run so hard as if my car was on fire. Simple fix though