loosing power

Hi,

I have 2008 Aveo 1.2 8V and have this problem:

When I bring rpm's on the car on 2000 no matter am I driving or in place, it's happening that rpm's are decreasing to 1500 and then again go to 2000 rpm's. I read on the forum that it's happen to have increasing in rpm's but didn't find this scenario. I don't notice any other problems like gear shifting. It's annoying in city drive were I am driving on 2000 rpm's and from time to time is loosing power (because decreasing of rpm's and have filling like car is jumping)
I connect the car on obd and read this code P0510-Powertrain Closed Throttle Position Switch.

Has anyone have similar problem and do you think that this will be fixed with TPS replacement or I need to replace whole throttle body.