Lewis Hamilton admits he hasn't been comfortable with the W06 since changes were made to the car at the Singapore Grand Prix.
After clinching the 2015 Drivers' Championship at the United States Grand Prix, Hamilton has found himself playing second fiddle to team-mate Nico Rosberg at the last two races with the German winning from pole in Mexico and Brazil.
Rosberg has also been on a roll in qualifying as he has now started P1 in the last five races while Hamilton's pole position drought goes back to the Italian Grand Prix.
The triple World Champion also claimed as the Mexican GP that Mercedes are being "extra warm" to Rosberg after he lost the title and he has now revealed he hasn't been comfortable with the car since Monza at the beginning of September.
"Since Singapore, there have been some changes to our car which seem to have shifted the direction of the waves, so I need to figure out why that is and how I can get back on it," he said.
"I have to try and improve in qualifying. Something has shifted in the car, I guess I have been a little bit less comfortable with it.
"I have only just noticed that is the only thing that has changed since things have changed, so maybe I need to go and do some studying and see what I can do to change that."