All eyes are on the Williams garage ahead of the third day of testing in Barcelona.
The struggling British team missed the first two days of 2019 running, amid rumours of design flaws and the potential departure of technical boss Paddy Lowe.
One Williams mechanic said it would be "a miracle" if the FW42 made its test debut on Wednesday.
Rookie driver George Russell, though, said he was "confident" Williams' predictions of running on Wednesday are accurate.
"Everyone is working as hard as possible to get it sorted," the reigning F2 champion added.
A team spokesman said running before lunch on Wednesday was "unlikely", amid speculation the car is finally en route from Oxfordshire to Spain.
It is an alarming situation for the once-great team's fans, including those of returning F1 driver Robert Kubica.
"As this goes on, surely someone will lose their job," correspondent Krystian Sobierajski, of the Polish broadcaster Polsat Sport, said.
Former F1 driver Marc Surer told Speed Week: "If the new car is again bad, I honestly do not know what will become of Paddy Lowe.
"This is his last chance."
