Romain Grosjean is concerned Haas is facing the same problems as China after struggling during Friday practice for the Russian Grand Prix.
Haas was unable to get its car set-up properly to get the most out of the tyres in China and failed to score a point for the first time this season. Having been "amazed" by the reaction from the team after the last race, Grosjean was hopeful of an improved showing in Russia but was left disappointed by Friday's initial signs.
"I think we have to make the circuit suit us," Grosjean said. "It is a very different one from China and I was expecting a bit more from the car today.
"I think we are struggling a little bit with a few issues that we may have started to have in China – getting the tyres to work properly. And that is the only big difference that we can see from the first two races. Hopefully things get better for tomorrow: we get the right answer and the guys will work hard to evaluate what we can do.
Having ended FP2 in 16th place, Grosjean called on Haas to continue investigating why the car has been more difficult to drive since the start of the Chinese Grand Prix weekend.
"We need to analyse. Since Friday in China I am not happy with my car, it was the case again today. We need to understand what could possibly go wrong and hopefully change it. I think there is a lot of work in progress, a lot of question marks. A lot of data. It is hard to trust everything but by tomorrow I think we find some good solutions."