Does a cold air intake really improve mileage?

colder air would help Performance

yes it should. i have a 03 chevy s10 and it improved my mpg by i few miles per gallon. it is more noticable in the highway than in the city though.

It might gain you 1%

First of all make certain all of your tires are inflated to the pressure marked on the sidewall of the tire - this may be 3 to 5 psi higher than the car manufacturer recommends but the only difference you will ever notice will be better fuel mileage.

Second check for dragging brakes.

You can improve your fuel economy by 30 to 50% simply by changing the way you drive.

Every time you apply the brakes for any reason you are throwing fuel away.

Think about it, why do you buy fuel? To provide motive power for your car to make it move. That motion once started can be continued with only tiny additions of fuel/power to maintain a steady speed. But what happens when you have to stop for a light, or stop sign, or traffic stoppage? Do you anticipate the stop and coast gradually to a stop from a half mile or farther away? (using all of the fuel value you are paying for ) or do you continue at full speed until you have to apply the brakes to stop the car all the way from 55 mph to 0 ??? When you apply the brakes you are taking motion energy, paid for by purchasing and burning fuel, and converting it into heat as the brakes do their job - stopping the car and throwing away the motion energy you have purchased.

I practice hypermiling driving techniques now and I can testify that my 2000 F-250 Super Crew pick-up truck, in which I was getting 12 to 13 MPG driving like an average driver, with absolutely no changes other than how I was (am ) driving it, I now consistently get around 18 and occasionally up to 19 MPG … that is a 50% improvement - just by paying attention, anticipating stops and slow downs, and slowing down to the speed limit or heavy truck speed limit if a lower one is posted as many states have.