Nico Hulkenberg expressed his frustration after a dismal practice session for Sauber in Canada.
Hulkenberg was eighteenth quickest in second practice, just a tenth of a second ahead of Marussia's Jules Bianchi.
"The car felt undriveable and mid-session we found a set-up error," he said.
"But even after we corrected that, we still had difficulties. I am not happy with the current set-up, we have to improve that and have quite a bit of work to do."
Team-mate Esteban Gutierrez ran towards the front during changeable conditions in FP1 but slipped back to seventeenth once the circuit dried in the second session.
"It’s quite evident we need to find a lot more speed," said the Mexican.
"We are definitely not where we want to be and we need to work as a team to improve and have a better overall speed."
Sauber secured a podium finish in Canada last year but head into this weekend's race eighth in the championship.