Charles Leclerc says Ferrari are “struggling like crazy” with a car they do not understand this year.
Leclerc finished seventh in Sunday’s Miami Grand Prix, while team-mate Carlos Sainz dropped from third on the grid to finish fifth.
“We have a car that is so incredibly difficult to be on the limit. We are very, very far away,” said Leclerc.
“I struggle to find an explanation as to why we are so far away in the race and so close in qualifying.”
Leclerc had the one-lap pace to start the race on the front row in Miami but crashed in qualifying. On race day the Ferrari exhibited its usual lack of pace.
“We are competitive in qualifying but once we come to race day we are struggling like crazy,” Leclerc, 25, said. “The window of our car is so narrow and whenever you get a little bit out it has huge consequences on the balance.
“It’s from one corner to the other and even in one corner sometimes you can have huge understeer which goes to huge oversteer and this is not ideal to have confidence in the car.”
The car was also very sensitive to wind, Leclerc added.
He said: “We have a lot of work to do. We need to find something. We have been struggling in the race since a little time now and we need to come up with some issues.”
He and team-mate Sainz said that the car was also exhibiting different behaviour on different types of tyre – and team boss Frederic Vasseur said that it was also different for each driver.
“With Charles we were much more performant on the hard (tyre), and with Carlos much more performant on the medium,” Vasseur said. “And from one lap to the other we were a bit inconsistent.”
Leclerc said: “It’s always an unknown whether the car is going to react well, whether the tyres are going to be in the right window.
“This is just very difficult also as a driver to gain the confidence and to adapt your driving because you get from one set to the other and the car is completely in a different window.”
Leclerc was Red Bull driver Max Verstappen’s closest challenger for the world title last year, before their season imploded with a series of race-management and strategy errors.
Those mistakes led to former team principal Mattia Binotto losing his job over the winter.
Ferrari entered this season expecting to be able to fight Red Bull for the championship again but find themselves in fourth place in the constructors’ championship after five races, also behind Aston Martin and Mercedes.
They introduced a new floor in Miami but it had little effect on the car’s competitiveness. Further upgrades are planned for the next race, the Emilia Romagna Grand Prix on 19-21 May, the first of three races on consecutive weekends.