Whenever the temperature outside drops below,say 40 degrees,my car idles really bad.After I get off the expressway going to work and stop at a light,the car idles up and down constantly for a few minutes then eventually will come back down to normal.Is this happening because there is too much cold air coming in and is it better to go back to a stock intake filter for d/d in the winter?By the way it's a 94 Accord.