slight hesitation

[le_ryan]

91 240sx ka24de 5spd 170,000miles rebuilt clutch system..ngk iridiums plugs, K&N drop in filter...i got a slight hesitation during a launch, seems to be at different RPMs but mostly noticable shortly after take off or gear change..also ive noticed, when im sitting at a light and try to hold the RPMs at a set number it seems to fluctuate up and down 200 to 300 each way .at normal idol its fine at 750....................????????help!