Romain Grosjean has revealed that his Lotus E22 prior to the Chinese GP was both "very unstable and unpredictable."
Last season Lotus finished fourth in the Constructors' Championship with 14 podiums including a victory in the Australian GP.
This season, though, is has been a very different story.
Not only has engine supplier Renault struggled with their new V6 engine but Lotus' E22 has also proven difficult.
Four races in Lotus have yet to score a single World Championship point although Grosjean believes they did take a step forward in China.
Speaking about his E22, he told Autosport: "It was very unstable and unpredictable.
"The front is less obvious on TV but it was both ends. We didn't even know which one was going to slide!
"It was down to last year's set-up not working for this year's regulations and the aero not working as we wanted. It's all linked.
"We had a big improvement in China, but it's not only one thing we changed; in the end it's a lot of things that make a good car."
The Frenchman billed some of the difficulties down to Lotus running set-ups from 2013 that didn't mesh with this year's new rules.
"We started a little bit on the back foot with baseline set-up, which wasn't the ideal for this year's regulations.
"It was very difficult to drive and not very efficient.
"They [the rulemakers] changed tyres, aerodynamics and power unit and we kept the direction we had last year, which was very good with E21 but didn't quite work with the E22.
"We have ideas now on how to set up the car to make it easier to drive. We just have to keep working."
But despite Lotus' current woes, Grosjean is confident there is better to come.
"I'm sure there's more potential in the car than what we are seeing right now.
"You never know. It goes quick in one direction and goes quick in the other [sometimes]. It's just work and getting things together.
"If we can move forward from there it would be nice to be back on the podium."
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