does ram air affect economy?

Colder air in the intake will make more power and MPG, no matter what Kim says.... Sorry, facts are but facts, might not be much, but it is a difference.

Not so sure you would get much measurable boost at cruise throttle/mph though, but the air temperature difference would make a slight difference in power output potential, thus RAISING vacuum.....

As far as lowering vacuum from just a small amount of boost you may get from the stock ram airs? Nah...... But, if in fact you could put a big enough air trap to actually make boost, then yeah, the vacuum in the intake would lower from the boost...