0958 GMT July 18, 2018
Sebastian Vettel's title hopes have been all but dashed after a crash in Singapore and engine troubles in Malaysia and Japan, AutoSport reported.
That has helped rival Lewis Hamilton open up a 59-point advantage in the standings with four races remaining.
Although Marchionne has expressed some frustration about a €59 spark plug costing the team so dearly, he also stated that Ferrari should "renew the commitment" to component quality control.
"It was a technical nonsense that had an impact on a car that costs millions of euros," said Marchionne in an interview with Italy's Class CNBC television channel.
"It's a problem we've probably ignored over time because it was never of much importance.
“Now we've had at least three occasions where we've really seen the devastating impact on performance. We'll fix it."
Vettel could have won the previous three grands prix, but only has a fourth place in Malaysia to show from the trio of races.
In addition to its lead driver falling out of serious title contention, Ferrari has dropped from 39 points behind Mercedes at the summer break to 145 points in arrears.
Marchionne believes that the pace of his team's car means the chance to pressure Mercedes remains as the season comes to an end.
"Without being arrogant, I think it is at the same level if not better than Mercedes' today," Marchionne added.
"I'm sure if we'd not had any problems like in the last three races, we would be having a different discussion.
"The season is not lost, there's still all to do. I won't talk of bad luck, I don't believe in it. The important thing is to not lose the confidence that has brought us so far.
"I'm delighted with what the team has done and I have tremendous confidence that in the next four races we will be able to close most of the Mercedes gap."