Random erratic rpm on Aveo 1.4L 2004 model MT Hatchback

Hello, i need help to my problem on my aveo,is there anyone who can help me pls. Tge problem of my car is randomly has abnormality in rpm,when i shift to neutral instead of the rpm goimg down it goes up to 2,000 rpm and up before it goes down to normal,specially when i step to my clutch to shift gear and sometimes when the car is not moving the rpm goes up and down like 1,800 fpm to 2,200rpm,i just want to know what are those possible cause of that symptoms so i can check the affected parts,if tehre someone who could help me i would gladly appreciate it,this is my email if you want to message me carlojohnaguilar@gmail.com,thank you and more power to you all