Lotus Renault driver Romain Grosjean has admitted to a confusing lack of downforce for the third weekend running, following a poor Friday practice session for the Chinese Grand Prix.
Grosjean said that the new configuration and the one from the Malaysian Grand Prix were tried but both left him off the pace of teammate Kimi Raikkonen.
"It's the third Friday of the season and the third time the same story," Autosport quotes Grosjean as saying.
"We went to the updates this morning and it was terrible then we went back to the last race specification and it was worse - from bad to very bad.
"All we can see is a lack of performance in downforce. We need to see now what we can understand. We cannot run the same set-up as Kimi because it doesn't work."
Grosjean ended practice in 12th, while Raikkonen was second-fastest.