Brasilia - Brazil's scandal-plagued former leftist president Luiz Inacio Lula da Silva and a tough-talking right-wing congressman lead voter intentions ahead of next year's presidential elections, a poll said Tuesday.Underlining the turmoil in Brazilian politics, the poll also confirmed plummeting support for the current center-right government, with 75.6 percent saying it is doing a bad job. Only 3.4 percent think the government is doing a good job, down from 10.3 percent in February.More than 84 percent of those polled disapprove of President Michel Temer's performance, while just 10.1 percent approve, the poll from the MDA research institute said.Temer is presiding over unpopular austerity reforms that he says will help accelerate Brazil's timid exit from its worst recession in history. He is also hobbled by several criminal charges of corruption, while much of his government likewise faces graft probes.General elections are due in October 2018 and Temer, who took over last year after Dilma Rousseff was removed in an impeachment trial, is not expected to seek a new term.With voters in an angry, anti-establishment mood, the poll commissioned by the National Transport Confederation showed high rejection rates for all probable candidates.Corruption trialsLula was hugely popular during his 2003-2010 two-term presidency but his reputation has been damaged by steep economic decline under his handpicked successor Rousseff and a mammoth corruption scandal.Investigators have revealed that swaths of political parties and politicians - allegedly including Temer, Lula and many others at the top - took bribes from big Brazilian companies for years in exchange for contracts.Lula has been sentenced to more than nine years in prison after being convicted of bribe taking, but he remains free on appeal. He also faces five more corruption trials, any one of which could result in him being imprisoned or barred from seeking election.However, the poll found Lula would easily win a first election round against all comers, with around 32 percent of the vote, compared to just under 20 percent for his nearest rival, the rightwing firebrand Jair Bolsonaro.Ecologist Marina Silva, who got 21 percent in the first round of the 2014 elections, would now get 11 to 12 percent in scenarios with Lula and Bolsonoro.In a runoff second round, Lula would also win, the poll found, hitting more than 40 percent of the vote in most scenarios, compared to between 15 and 29 percent for potential runners-up.Former paratrooper runs secondBolsonaro, a former paratrooper who revels in making provocative comments against homosexuals and in support of torture during Brazil's 1964-1985 military rule, runs a strong second in most scenarios for first and second rounds.Without Lula in the race, Bolsonaro would win a run-off round against several more establishment candidates, the poll found.For example, he'd win with 28 percent to Sao Paulo Governor Geraldo Alckmin's 23.8 percent, the poll found, and by 28.5 percent to 23.9 percent against Sao Paulo Mayor Joao Doria. However, he would lose narrowly in a head to head with Silva.The MDA poll interviewed 2,002 people between September 13-16.