Mishra said before the death threat abuses were also hurled at him for not receiving the call from an unknown number.
"I don't know who's behind these threats but I am not afraid of anyone," he said.
Kapil Mishra, who accused Chief Minister Arvind Kejriwal and minister Satyendar Jain of corruption and other irregularities, said he would sit on hunger strike from Wednesday until the "truth" comes out.
Accusing AAP leaders of misusing party funds on foreign trips, Mishra said, "if there is nothing to hide, them provide the details of foreign trips of five AAP leaders. Also inform the public about the source of money".
"This matter is serious and related to the country and the law. You will have to make information public," the Karawal Nagar MLA, who was suspended from the primary membership of the AAP, said.
"Until these details are made public and the truth comes out, I will do 'Satyagraha'. I am on hunger strike from tomorrow..," he tweeted.
Mishra, who also wrote an open letter to Kejriwal challenging him to a poll battle, said he is still waiting for a reply.
Mishra on Tuesday filed three complaints with the Central Bureau of Investigation against Kejriwal, his relatives and some AAP leaders including health minister Satyendar Jain.
He sought details about the foreign trips of Sanjay Singh, Ashish Khetan, Raghav Chadha, Satyendar Jain and Durgesh Pathak and threatened to go on a hunger strike if the AAP failed to do so.
He had also submitted to the ACB documents to back his allegations that Kejriwal had delayed a probe into a Rs 400-crore water tanker scam.