What could be reason for not getting more than 20 MPG in a Chevy Metro?
try a tune up, new plugs, plug wires, air filter, oil change,
and maybe the o2 sensor, or it could possibly be a fuel leek. good
Just got 1 other answer and that's age of engine. Carbon buildup
in pistons or seals in the head. Many many things can lower
mileage, but just plain getting old is something to consider. We
are talking about cars over 8 to 11 years old.