
Is 40 Miles Per Gallon Good?
Audi. Audi S5 – 30 MPG Highway. of 30. BMW. BMW M340i – 30 MPG Highway. of 30. Ford. of 30. Jaguar XE S – 30 MPG Highway. of 30. Richard Pardon. Does a vacuum leak affect gas mileage? A vacuum leak at the intake manifold gasket, in the manifold itself or any of its vacuum hose connections can lean out the air/fuel mixture and cause the engine to misfire and deliver …