Integrated Child Seat Belt problems of the 2007 Chevrolet Impala

Dear NHTSA, please investigate the following serious concerns that have affected my vehicle safety in addition to other chevy Impala drivers: vehicle: 2007 chevy Impala. 65,000 miles, 1 owner, Impala LS 3. 5 l v6 safety concern # 1- intermediate steering shaft - gm refuses to acknowledge the seriousness of this problem. My vehicle's steering wheel clicks during driving & temporarily jams causing a feeling of disconnection from the road. It has caused a momentary loss of steering control, and I feel this is a serious safety concern to be addressed. This is an ongoing design problem for many gm models(as per my google search), gm refuses to make corrections to the design nor issue a recall. --------------------------------- safety concern # 2- power steering pump- power steering pump loosing effectiveness & turning performance, meaning pump may be failing at any time. This too is another common problem with chevy models. Please encourage gm to expand power steering pump recall to include chevy Impala models. ---------------------------- safety concern # 3- rear back seat center seat belt looses tension when used in conjunction with infant car seat. When vehicle goes around 30 mile/hr turns or mild turns, seat belt locking mechanism(the one that holds the seat belt tense during braking) disengages & permits the seat belt to loosen causing child seat to move across the seat & or in one serious case with my son flip sideways(luckily my wife caught the seat as it tipped sideways). I have followed all safety instructions as per car seat manufacturer (evenflow aura travel system). This is a concern, since the tension only stays firm in abrupt stops, this leads me to question the safety in a roll over scenario. I have since used the seat level car seat hooks since the past few events( this greatly reduces the ease of sharing the car seat between vehicles). My other vehicle(Nissan altima) has no such problem, the tension mechanism on the altima remains firm.