starts sounding like a yetti

hey i just registered here cuz i just bought a 98 zx2. i bought it mostly cuz i didnt want to be some idiot with a honda and burnin rice. but ive been messin around with it and sometimes when i let it idle in my driveway it starts to shake a little bit and makes a sound like a yetti or chewie from star wars, any ideas on what this could be?

most likely be the A/C compressor cycleing on and off

thank you