The Franco-Swiss driver finished 10th, over 90 seconds behind winning team-mate Kimi Raikkonen, and blamed the performance on a car problem.
He refused to give too much detail about the problem, referring to something in the set-up of the car that was not as expected.
AUTOSPORT understands that the team has not found any evidence of a specific component problem that needed to be fixed, but there are no doubts that Grosjean's car will be in good shape this weekend.
"We did find that we were missing a few things and that the set-up was not exactly what we thought it was," said Grosjean when asked by AUTOSPORT about the problem.
"It was not a set-up mistake, but it was something that did not go as planned for some reason.
"There was just no downforce, starting with massive understeer and finishing with big oversteer.
"Going to the grid, it was quite obvious because Turn 2 was not flat.
"Hopefully the issue was solved and from there we will recover our downforce."
Grosjean anticipates that the car will feel better at Sepang.
He is also hopeful that Lotus will be able to perform more strongly in qualifying and that the deficit to Red Bull in Melbourne was not representative.
"When you fall from a horse, you want to jump back on as soon as you can so it's good that we have a race this weekend," he said.
"I'm looking forward to driving the car in P1 and feeling everything back to normal.
"In Melbourne, we were pretty quick on a single lap and in P3 we were there [on the pace].
"There is no reason why we are 1.5 seconds slower in qualifying and I don't think it will be the case again."
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