pls I need to know Nissan AD wagon Y11 Fuel consumption limite

Don't quite understand your question can you be more specific is to the problem

sory about that, I'm using Nissan AD wagon Manufactured by year 2000 model no:Y11, it's works 8 km per liter,so I need to know what's the normal(nissan AD wagon) fuel consumption level & please advice, how to Increase fuel consumption level in my car.

Give it major tune-up and flush out your fuel system-start here

if you can pls tell me how to do that.

Your best bet here is just bring it in to a shop and have them do it-