Ok...Whats the Deal?

I have a '98GT 5spd. When I shift into 2nd, or shortly there after, my car drops power..Kinda feels like the fan is coming on. It does it even when the air conditioner is turned off. I'm going to replace the plug wires, and just do an all around tune up to see if that helps. What do you guys think is the problem? :scratch:

Forgot to mention that this lag immediatly goes away right after 3k rpm.