Hamilton said Ferrari had upgrades coming to the car in forthcoming races – these would follow a new floor that was introduced at the previous race in Austria.
The 40-year-old said he wanted “a consistent balance, a car that turns at a low speed, just a more stable car”.
He added: “We were looking great through this weekend. In practice. we were always right up there. Still weren’t able to fully extract everything in qualifying. And then the race is a little bit harder. So that’s where I want to get stronger.”
Hamilton’s third fourth place of the season means he is still to finish on the podium since joining Ferrari at the start of this season.
Team-mate Charles Leclerc finished second-last in 14th after making the wrong call to come in for slick tyres on a damp track after the formation lap. His race spiralled downhill from there.
Leclerc said: “We were kind of nowhere the whole race, and when I say nowhere it’s like really nowhere, I was a second off (the pace) and on top of that I was doing lots of mistakes.
“I was really struggling to keep the car on track so it was an incredibly difficult day.”
Team principal Frederic Vasseur said: “The main issue we had today was that we struggled a lot when we were in the dirty air to overtake.
“We spent our lives overtaking sometimes 10 laps and then we were much faster. I think it was a difficult weekend, difficult for the strategy.”