The Verdict: Not eligible
A grandparent cannot pass Indonesian citizenship to you, because it passes only from a parent who was Indonesian when you were born. If your grandparent or parent was Indonesian and later gave it up, you may be able to live in Indonesia permanently instead.
The Citizenship Law of 2006 (Articles 3 and 4) has no generational rule: it gives citizenship to the child of an Indonesian, and nothing to a grandchild whose own parent was not Indonesian.
What works instead: the Global Citizenship of Indonesia scheme gives a permanent stay permit to former Indonesian citizens and to their children and grandchildren, as long as the ancestor held Indonesian citizenship at some point since 17 August 1945. Our Diaspora quiz for Indonesia walks through it.
Check your parent first. If they were born Indonesian and later took another nationality, they are a former citizen, and their own application may be simpler than yours.