Hi , Iam owner of Octavia Ambiente 1.9 tdi engine, needed maual of manutency or the way of improve performance

Improving on performance you dont have to look any further than here there are hundreds of threads covering all sorts of improvements you can make which wont be covered at all in the service manual

Is it the original service manual that came with your car your looking for or just a general maintainance guide ?

If its the later pick up a haynes manual as it covers all the routine stuff you need to do plus so much more its worth having for reference anyway