Sergio Perez has revealed delays caused by an anti-roll bar issue compromised his practice running for the French Grand Prix.
The Mexican was only 10th quickest in second practice after completing his fastest lap later in the session than the majority of the field.
The Red Bull driver was left waiting in the garage throughout the qualifying simulation period before eventually setting a time that was one and a half seconds off the pace of Carlos Sainz's Ferrari.
"We were having some delays," explained Perez, who also narrowly avoided hitting a barrier in first practice following a spin.
"Nothing really going on, a bit of an issue with one of the anti-roll bars but nothing major."
Perez uncomfortable in Red Bull
Perez's Red Bull team-mate Max Verstappen struggled with the balance of his car, with the RB18 experiencing understeer, especially through the long right-hander at Le Beausset.
On his own feeling after his truncated running, the Mexican driver conceded: "I am not very comfortable at the moment with the car.
"There is some good work and understanding to be done overnight. We need to try to pick out the best pieces for quali and the race.
"They have been very short stints on that soft tyre but it is what it is. Hopefully tomorrow, we are able to put it all together and be in the fight."