Mercedes team principal Toto Wolff has revealed the team continues to fight "a few gremlins" despite a "night and day" improvement in Australian Grand Prix qualifying.
Lewis Hamilton and George Russell finished fifth and sixth to complete a turnaround from Friday's representative practice two session, where they finished 13th and 11th respectively.
Hamilton had suggested on Friday that nothing the team had changed was making any difference.
Asked if purely changing the W13's set-up could find improvement, Wolff explained: "I think set-up directions are very, very important and we have seen the drivers were much happier with the car today than yesterday.
"Night and day were the words that Lewis chose.
"We are talking a couple of tenths, maybe a little bit more. The long runs will be interesting but there is a gremlin in our car, or a few gremlins, that we haven't found yet.
"That is something we need to continue to analyse and look at the data. As I have said before, it is physics not mystics."
Mercedes still "learning" new car
Mercedes' positions on the grid for Sunday's race have been boosted by Fernando Alonso's crash in Q3 that also squandered Carlos Sainz's best lap, leaving both drivers behind Hamilton and Russell.
Addressing the team's performance, Wolff said: "I am satisfied with the result today.
"Obviously, if you correct for Sainz and Alonso, it is less good but it is still solid in the top 10 which was not a given with the closeness of the front end of the midfield.
"I think we are just learning the car, we are learning the tyres. Nothing this weekend has unlocked the aerodynamic potential or has reduced the bouncing. We are still at the same place and that is why it doesn't make any sense to bring updates.
"You confuse yourself even more. Maybe it is even the fact that the more downforce you bring, the worse the bouncing gets so we are still learning."