96 GT blue smoke

I have a 96 GT 102,000 mi. The car never smokes on start up, or when jumping on the highway, or reving engine. When it sits at an idle for a minute or two and you hit the gas it will put out a little blue smoke once, then it clears up. Guessing it is valve seals ? A friend has a Crown Vic 4.6 that does the same thing. ONLY smokes after idling, like at stoplight, which looks great. Thanks for any help......