1994 Buick Century car leaps forward from start.

I have 2 questions, I just bought this car, and two things I noticed, #1 From a stop when I first hit the gas, it seems like a slight hesitation then like leaps forward, almost like a jerk forward, runs fine otherwise, all fluids nornal.

#2 When I put the heater on full at a stop, it seemed like she wanted to stall, "a little shaking", it starts and runs good, lights ok, but if the heater is turned on while in park, or the rear defoger, or the brakes pushed, the headlights and inside lights will go dim slightly.