The former Selecao striker, who is the joint-leading goalscorer in World Cup history with 15 goals in 19 games, has been disappointed by the manner in which his country have progressed to the last eight.
He has admitted that Brazil's struggles include a misfiring forward line, which has netted just one of their eight goals at the tournament, and urged Scolari to freshen up their attack for the all-South American clash.
"We are waiting for a good performance by Brazil," Ronaldo, who won the World Cup in 1994 and 2002, told reporters.
"We are not playing well. I am disappointed with the first four matches. I think he [Scolari] will change something. I don't know what.
"They aren't playing well," he added on Brazil's strikers. "There are no secrets - my advice is to run a lot - but it's not easy to play like a No 9, even if you have Neymar playing with you."
Scolari is believed to be considering abandoning his recognised strikers for Brazil's last-eight tie.