Hmmm,
Not good.
Things to check would be AFM, maybe give it a clean - there's a thread on this in the maintance section.
And I've heard that sometimes the temp sender can crap itself. So when it's cold, it's actually sending a reading of being hot, so the ECU adjusts the mixtures to a hot engine.
Other than that, maybe your plugs are clogged up???
I hope you get it sorted out. Let us know how you go.
J