Kimi Raikkonen says his Lotus team has work to do overnight in Malaysia after a frustrating day of free practice at Sepang.
Both Raikkonen and teammate Romain Grosjean were comfortably in the top 10 in the first session of the day, but the Finn was only 15th in the afternoon with Grosjean dropping to ninth as the team struggled with tire management.
"It was probably not the best day," Raikkonen told reporters in the Sepang paddock on Friday. "It was difficult to find the balance.
"We have some work to do on the setup side. The long run was OK, but at the end the car was undriveable. We had some issues with the KERS, too."
Raikkonen said that he didn't know if Lotus would be in the top 10 when it came to qualifying, and he added that he was not any happier with his power steering set-up either, describing the feeling as "the same."
Grosjean was slightly more upbeat than his teammate, but shared Raikkonen's view that the team still had a lot of work to get through.
"It is not an easy track to deal with and finding a setup is quite hard," said Grosjean. "We are working on it between the two cars and have some answers of what we should and shouldn't do.
"We are still looking at the data and working hard to get the best car for tomorrow. If we find the perfect setup I think we can be at the same level [as in Australia]. If we are still in between the best [setup] and a good one, maybe we won't be as good as we were."