[Christ]

that's normally cam or ignition timing, that causes it to die when you hit the gas. it's basically that the timing is probably far enough off that it's "flooding" and when the engine spins over a couple times to get the excess fuel out, it goes back to a stoichiometric a/f ratio, and will burn better, so it "surges" up in RPM.. this usually takes just a second, as the engine is spinning quite fast, and expelling excess fuel into the exhaust at every exhaust stroke.

When you let the car warm up, and you're driving it around, feel down by the shifter on the floor, and up by the floor vents.. if your floor is hotter than normal, that means your cat is getting hot, it's either plugged or you're dumping fuel.