It really depends on WHERE you live. The owners manual on my 04 Nissan Frontier says the recommended oil is 5W/30 all seasons, but I run 10W/30 Valvoline ALWAYS.
Use 5w30 weight oil only just as recommended in your owner's manual.
10w40
5w30
5w20
5w-30
5w30
5W-30 is most recommended for a 2006 Chevy Impalawith a 3.5 liter motor. 5W-30 is most recommended for a 2006 Chevy Impala with a 3.5 liter motor.
10w30
10w30
Should be marked on the oil fill cap
5w20 synthetic blend motorcraft recommended
The Ford recommended oil weight is 5w-20