I have a Focus ZX3 (2003) US.
In changing the engine oil myself, I am confused at the amount
of new engine oil that I need to fill in. Is it 4 qts of 4.5
qts that I need to pour in? I wait the old oil to drain for about
When I filled up 4.5 qts over the thanksgiving, I seem to be
getting worse mileage of 30 mpg now (used to be 33-34 mpg).
The dip stick reads the engine oil at top mark with 4.5 qts
and the lower mark with 4.0qts.