Williams was the worst of the midfield teams on both qualifying and race pace in Australia, with Valtteri Bottas finishing a lapped 14th in the race.
Both Bottas and team-mate Pastor Maldonado complained of a lack of grip and struggled with switching the tyres on and managing degradation and wear. Williams had to backtrack the car closer to its launch specification.
AUTOSPORT insight: how it all went wrong for Williams
But Coughlan already has ideas for ways to improve the car that are not reliant on upgrades, with little time to manufacture new parts for Sepang.
"We are disappointed with the performance and I don't want to blame the tyres," said Coughlan when asked by AUTOSPORT about progress.
"We have got some issues with the car but we've got some direction and we've been looking at the data.
"This is the first time we've had running at a track like Melbourne and we did learn things.
"We have some plans moving forward and we will implement them for Malaysia.
"Certainly, Malaysia will be an interesting Friday for us."
Coughlan is also hoping that the higher track temperatures in Malaysia will make it easier to get the best out of the tyres.
In Australia, the team struggled not only with switching on the tyres, but also with wear and degradation.
"That [the higher track temperature] is going to be an advantage, to go somewhere where maybe the tyres will come to us a little bit quicker," said Coughlan.
"But we still have some work to do in terms of car development."
Maldonado, who failed to finish in Australia after touching the grass under braking for Turn 1 and spinning into the gravel, is confident that things will improve quickly.
"I think we can fix the problems," said Maldonado.
"I think it will be much easier to understand the car in Malaysia because it's a proper track and the aero works more than at Melbourne.
"I'm quite confident that we have good engineers, good guys and we are all working together to fix it. I think we will."