The weakening/slowdown/contraction of consumer spending, which is(was?) the major driving force of US economy(the driving force of many US economic activities), damages/damaged US economic growth.
US economic growth is at standstill/damaged/hindered by the weak(weakening) consumer spending, the major driving force of US economy.
US economic growth is at standstill/damaged/hindered by the weak consumer spending, which is the driving force of many US economic activities.
Consumer spending, the driving force of many US economic activities, is weakening further, which severely damages US economic growth.
Consumer spending, the driving force of many US economic activities, is weakening further, severely damaging US economic growth.