really bogs down off the line

[sporty240]

i have to slip the clutch a lot if i want to have even a semi-decent launch. otherwise it will "diesel" (like it should be in a lower gear) until about 3000 - 3500 rpm. it's pretty bad. i wonder if this is a common S13 thing or something's fouled up in there. I've got an injen intake and bosal muffler with new cap rotor plugs and ngk wires. it perks up afterwards, it's just an off-the-line problem.