new 86

I've wanted one of these forever, and last weekend i got one for 2K. Awesome car, but comming out of first sometimes it gets this occelation. Every now and then its really violent and you have to get outta gear to stop it from breaking the input shaft. It doesnt seem to do it as much when its hot. Do you think that could be a loose throttle cable? I wouldnt imagine itd be a warped flywheel... ?