I am planning to do valve clearance (Tappet adjustment) of my Honda City 2006 IDSi for the very first time (72,000 on odo). Need answers for the following questions from seniors/experts

1. Is it necessary? My RPM is stable and engine is quite, however very minor vibration is felt during idle

2. I went to Honda dealer in Islamabad and he told me that the whole exercise will take 4-5 hours (as the engine should be cool) and charges will be Rs 2,500. The question is that is this tappet adjustment a very technical job and can only be done by authorized dealer only or it can be done by good mechanic?

3. If it can be done by any mechanic, can someone recommend me any good mechanic in Islamabad and charges also.

4. Shall I do the throttle body cleaning also at the same time?

My car is giving me average of 12-13 km/l in city driving and 16-17 on highways with very light foot.