With its small budget, the lean and mean Silverstone based team finished an admirable fourth overall last year.
The team then signed up a $20 million new sponsor and painted its car pink for 2017, but Mexican driver Perez admits Force India is currently struggling.
“We’re missing speed both on one lap and in race pace,” he said ahead of the Chinese grand prix.
“We are currently the seventh or eighth fastest team in the field,” Perez added.
It is known already that, after Perez and teammate Esteban Ocon bulked up over the winter, Force India asked them to then lose that weight to help the team’s competitiveness.
And Germany’s Auto Motor und Sport said the big update to fix the current problems – including smaller sidepods – will not be ready until Montreal in June.
Until then, Perez said: “We have to take advantage of every opportunity that is offered to us. Just like in Australia. This was a great weekend for us with a result we did not expect.”