Romain Grosjean says ongoing problems in getting grip from the tyres is compromising Haas' one-lap pace, as both he and team-mate Esteban Gutierrez were knocked out of Q2 in Canada.
Grosjean was 15th fastest in the second session at the Circuit Gilles Villeneuve, with Gutierrez 14th, though both will move up one position due to Daniil Kvyat's penalty.
Grosjean scored 18 points across the opening two races but Haas has slipped back through the midfield in recent races, and the Frenchman has pinpointed the tyres as a primary issue.
"The car balance is not miles off, but we just don’t have any grip from the tyres," he said.
"We’re not getting them to work properly. For some reason, we had it at the beginning of the year, but we haven’t managed to bring them back in the window since.
"That means you can’t really drive the car as you would like. Yesterday, our long-run pace was quite good, so hopefully the race tomorrow is better."