Rpm Drops 200-300rpm when throttle is used

[jesteratc]

Hey, wonderin if anyone else has delt with this crap.

89 240sx Hatchback Automatic....

I will drive my car spiritidly sometimes leaving work.Punch it around a few corners, and the trans will shift at redline.

Then it starts to act up. I cant blame it tho.

But what happens is i will come to a stop light, and when i press the gas to take off, the rpm will drop, and almost feel like fuel is gathering, then black smoke comes out, then the car launches.

I can press the gas lightly from either take off or while driving/coasting and the problems are minimized, but im trying to find out what is causing the problem.

This situation doesnt happen if i dont beat the car.

So basically....

After hard driving, when the gas pedal is pressed, the idel drops for a second, then comes back violently.

Any info is much appreciated.

Thanks,

Andrew