Esteban Gutierrez says Haas is still seeking a solution to the fuel sensor problem which curtailed its first day of the second Barcelona test.
Gutierrez resumed testing duties for Haas on Tuesday but completed just 23 laps before the issue occurred in the morning. It followed an encouraging first week at the Circuit de Catalunya.
Speaking about the limited running, Gutierrez said: "Well, it's not ideal! There's not a lot to say. We have a solution to find, which the team is working very hard at the moment to get back on track. Let's hope that we can fit in three days what we had in four days.