after being absent from my life for 16 year my father is now looking to be in my life again. If I don't live with my mom but my aunt and uncal who are my leagal gardians for the past 4 years could he have a good chance of geting custody?

There are a lot of reasons why this could be difficult to answer based on what details you gave me. The answer may depend on the reason why your Aunt and Uncle were appointed guardians. If they were appointed guardians, your father may likely be able to get visitation, but it may be difficult for him to obtain custody, especially if he has been absent for a long time. Remember the court looks at what is in the best interests of the child, and if you have a happy and stable home they may not want to change that. It is up to the judge's discretion. Since you are almost 17 the court will hear your opinion on the matter. If your father has already filed papers your aunt and uncle may want to speak with a lawyer.