I have manual City 2006 IDSi (68,000 K driven) and I am not a person who keeps visiting mechanics every now and then. What I did was to keep essential items (Engine oil, oil filter, air filter & plugs) change on time. Nothing else is changed and no problem as of now. The car is driven about 30,000 on CNG and is on petrol for the last 1 year.
The car given around 13 km/l in city and 16-17km/l on long (both with soft pedal and max speed of 110 km/h)
Do you think i need to do anything else like throttle body, tappet (Valve clearance) etc. The only issue I feel now is little lag when I accelerate in 1st gear but it could be due to plugs which need replacement i think.