By GLORIA MARINA

The FBI is investigating whether the U.S. Neutrality Act has been violated by a Cuban exile allegedly plotting terrorist acts against foreign governments in Miami, a spokesman said Tuesday.

The Neutrality Act prohibits the planning on United States soil of any acts hostile to another government.

The FBI began investigating Gaspar Jimenez Escobedo as a result of information received from Mexico, where he is wanted on a charge of murder in the slaying of a Cuban intelligence officer.

According to the information, members of the Coordination of United Revolutionary Organizations (CORU), the Young Men of the Star, and Abdala, a students' group, plotted to execute "a series of terrorist acts on an international scale," and did some of their plotting in Jimenez Escobedo's 5250 SW Second St. home.

Mexican authorities haw not initialed extradition procedures against Jimenez Escobedo, and he has not been arrested, because U.S. authorities do not have sufficient evidence against him, authorities explained.

The terrorist acts, according to the reports sent by Mexican authorities to the FBI, included bombing the Cuban embassy in Mexico and Cubana Airline offices, and highjacking a Mexican passenger plane, and one carrying the son of an unidentified Mexican socialist leader.

In July of last year, Jimenez Escobedo, a 40-year-old employee of Florida East Coast Railways, was arrested in Mexico, along with 28-year-old Cuban exile Orestes Ruiz Hernandez. Both were accused of trying to kidnap Cuban constul Daniel Ferrer Fernandez and of killing Artanan Diaz, a Cuban intelligence officer.

Jimenez, a member of Dr. Orlando Bosch's Cuban Action, one of the groups belonging to CORU, escaped from the Mexican jail in March of 1977, after bribing a supervisor and a guard. A month later he was back in Miami, where, because there were no U.S. charges against him, he was a free man.

Ruiz Hernandez, however, remained behind. His own escape attempt was foiled when authorities discovered a tunnel he was digging.

The subsequent plots, the Mexican reports charge, were to assist or follow Ruiz Hernandez escape.

The reports name several other Cuban exiles, other than Jimenez, whom they identify as the leader.