AsSalamOAlaikum
Your Rpm sensor and Tp sensor need proper calibration through computer setting.
Santro is very excellent car ,all you need is a perfect mechanic and electrition.
Spark plugs need to be replaced at every 15000 to 18000 km.
For all sorts of problems in santro you can call us or share your problems here.
CARTECH AUTOS
Santro specialist
Syed Sadat masood
03224450322
320-johar Town
Lahore