LIMA, Peru (AP) _ Alberto Fujimori, the Roman Catholic son of Buddhist immigrants, counts on Protestant evangelicals to help him defeat novelist Mario Vargas Llosa, an agnostic, for the presidency of Peru.

Fujimori's parents immigrated to this predominantly Catholic country from Japan in 1934. He finished a close second to Vargas Llosa in a field of nine candidates April 8 and a runoff between them is scheduled for June 3.

Vargas Llosa, an advocate of free markets, was the favorite, but Fujimori surged late in the first campaign despite a shortage of advertising funds. Polls show the once-obscure agronomist leading his famous opponent less than three weeks before the runoff.

Evangelical Christians, responding to Fujimori's message of work, thrift and honesty, carried his campaign to areas the poll-takers never penetrated.

They spread the word in revival meetings, knocked on doors in Lima slums and the violent Peruvian countryside.

Raul Gonzalez, a sociologist, attributed Fujimori's strong support in regions where leftist guerrillas are dominant to the grassroots work of evangelicals and the diminishing presence of the Catholic Church.

''The evangelicals have been working door to door, almost person to person,'' he said. ''That has been very important.''

Evangelical denominations have grown rapidly in Peru. Sociologists say they offer moral and social discipline in a nation being driven to anarchy by economic crisis and the leftist insurgency.

About 1 million of Peru's 22 million people attend storefront Protestant churches and the number has doubled in five years, according to the churches. The largest denomination is the Assembly of God, which has 1,152 churches in Peru.

The evangelical movement also has grown elsewhere in Latin America. Efrain Rios Montt, a retired army general and evangelist who led a Guatemalan military government in the early 1980s, is a leading candidate for president this year.

Jaime Althaus, a Peruvian anthropologist and newspaper columnist, said the evangelicals reflect the conservatism of Change 90, embodying the ''values of work, effort, savings that are at the base of grassroots capitalism.''

Fujimori recruited Carlos Garcia, a Baptist preacher, in November as a candidate for one of the two vice presidencies. Garcia later was elected president of the National Evangelical Council, an organization of Protestant churches ranging from Methodists to Pentacostals.

Evangelicals made up about one-fourth of the 200 congressional candidates for Change 90, Fujimori's party. Many young party workers belong to the movement.

Change 90 won about 50 of the 240 congressional seats April 8, but the official results have not been announced. Fujimori got 30 percent of the vote for president, two points less than Vargas Llosa.

''The evangelicals like Fujimori because he is honest and he is the only truly independent candidate,'' said campaign worker Ricardo Massa, a born- again Christian.

Massa's uncle, Alejandro Rojas, is an evangelical minister and general secretary of Change 90.

Guillermo Yoshikawa, a Methodist minister and Change 90 congressional candidate, addressed a letter to the ''evangelical public'' urging churchgoers to support the party's candidates.

''No longer will we have to ask 'favors','' it said. ''Our brothers in parliament will make sure that the rights granted us in the constitution become a reality for all evangelicals.''

Catholic church officials claim Change 90 supporters sent flyers to convents, monasteries and groups of Catholic mothers urging people to vote against Vargas Llosa because he is an agnostic.

Cardinal Augusto Vargas Alzamora has said the church would not endorse a presidential candidate, but the Apostolic League of St. Pius X, a conservative Roman Catholic group, declared in its monthly newsletter:

''If the evangelicals come to power, sooner or later Peru will become Protestant. No more masses. No more processions. No more saints.''

Fujimori says attempts to portray Change 90 as a disguised religious crusade are unfounded.

''I'm not preoccupied by religion and I don't discriminate on grounds of religion,'' he said, but added, in an obvious reference to his opponent: ''I believe Catholic people would prefer a Catholic president.''