Pakistan's fragile PPP-led federal government got a lifeline today when its biggest ally MQM announced its return to the coalition after its demands like the rollback of petrol prices were met.But the Muttahida Qaumi Movement leaders, who held crunch talks with Prime Minister Yousuf Raza Gilani, said the party will not join the federal cabinet.The return of the 25 MQM members to the government benches restores the Pakistan People's Party-led government's majority in the parliament at 183 seats out of 342.