Brazil have been criticised for a string of unconvincing performances, only scraping past Chile in the round of 16 after a penalty shootout.
And ahead of Friday's quarter-final battle against a Colombia side that has won all four games so far, the two-time World Cup winner has urged Scolari to reawaken his attack.
"We are waiting for a good performance by Brazil," Ronaldo said.
"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."
Strikers Fred and Jo have netted just one of Brazil's eight goals between them.
"They aren't playing well," Ronaldo said. "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."
An expectant nation's hopes hang heavily on Neymar but Ronaldo has backed the 22-year-old forward, who has scored half of his side's haul, to keep thriving in the spotlight.
"I see Neymar and I don't think that he really thinks about the pressure," Ronaldo said.
"He's very calm, he's relaxed. He's just like a kid, just thinking about playing well and score goals, even if the pressure is so big. He is okay, he can handle it very well."
On his hopes for the final showdown on July 13, he added: "I dream with a final match between Brazil and Argentina."
Scolari is expected to stick by Fred, with Hulk in support, but he will be forced into at least one change further back because holding midfielder Luis Gustavo is suspended, Paulinho's expected recall set to allow Fernandinho to play in a deeper role.