hi needing a little advice on my car the, other day when i finished work i started up my car to let it warm up for a gd 25 mins before i drove it. As i started to drive it all was gd untill i got into vtec it was pretty smokey not black smoke or anything, and i thought is this right is it ..? about 2 miles down the road i engaged vtec again and there was no smoke this time, why is this..? or could it just be cold weather any advice would be great thanks