Yes, unfortunately i read a lot of topics in here regarding engine knock, poor/rough idle etc.. I also noted bad (very bad) suggestions to that problem such as remove cat and that it is a 3 cylinder engine so rough idle is normal etc.
NO, rough idle is not normal in the 1kr-fe engine. It never happened to me in 40k i have been driving the car (car is now 44k) I trust only one professional mechanic in the world {his name is service manual} I have always serviced the car myself with toyota genuine parts. I replaced plugs and cvt oil at 40k, plugs were like new so i cleaned them in a plug cleaning machine, replaced their washer cos it can be used only one time and are ready for use at 80k, cvt oil was very dark, with few iron dust on the sump magnets so it was worthed replacing it and cvt feels more aggressive when driving) brake pads, and use shell helux 5W30 every 4k. Now i cleaned all sensors and that's it. For me it's just a hobby but i read a lot of how things work. If i ever need a mechanic i make it a point i will have to be there and we discuss what to test before he do the work. OBD makes life easy on the 1kr-fe
Toyota spends milions of $$ in research and development and the 1kr-fe was awarded engine of the year under 1ltr for 4 (four) consecutive years and that was with a cat installed lol.
Yes my car is a Vitz 2009 Japan import I bought it while i was there from a friend. the car belonged to his father who died in a work accident. It's oddometer was reading 4227 kms. (the car was brand new, he even payd the jevic certificate. To show the oddometer readings were genuine i was present during the inspection and it was nice to see very expensive tools reading hidden ecu chips)