I am a US citizen. Grandparents were born in Austrian Hungarian Empire. Am I eligilble for Austrian pport?

Unlike Austrian citizenship, Hungarian citizenship is not lost when you take up a new citizenship. You have to intentionally revoke it if you don't want to be a citizen of Hungary anymore so are you sure neither of your parents was a Hungarian citizen? Because you could only obtain a pport through a citizen parent. Otherwise, you have to go through immigration and fulfill the residency requirements. An additional requirement in that case is that you have speak the native language of the country, too.