I have a 2001 Sportage, 2wd, auto, convertable, etc... Recently, it started missing when taking off. At first, it was pretty subtle and I thought the tranny was slipping (it was replaced once, under warranty). Now it's pretty rough, but only seems to happen when first started (cold or warmed up) and put into drive. Once I get moving, it seems to go away. I have no CEL on. I replaced the valve cover gasket and plugs about 3 months ago, because it was leaking. Any ideas?

Thanks much,
Kris