Nico Hulkenberg is urging Renault to improve its reliability after a DRS issue forced him into retirement in Sunday's Japanese Grand Prix.
The German driver was running comfortably in the top ten when the Renault's rear wing flap stuck open into Turn 1, the car's behaviour catching Hulkenberg off guard and forcing him to pit.
"Normally when you go off the throttle or de-activate it, it comes back down," Hulkenberg told Motorsport.com.
"In this case it got stuck open because there was a metallic shim part that was broken, so it sent that hydraulic mechanism out of order. It was blocked, basically.
"It happened into the first corner. It felt a bit weird, then another corner a bit weird. I thought this is dodgy!
"Then I looked in my mirrors and saw it was open, and that was clear. It was not so good in Sector 1, to be honest, a bit scary!"
Hulkenberg has been on the receiving end of several mechanical and engine failures this season with Renault. In addition to improving its performance level, the Hulk insists efforts must also focus on reliability.
"Absolutely, it's not great. But it's part of the whole development that we go through," he said.
"It showed one weakness again, and the car often is not good enough reliability-wise, and also performance-wise of course. There's still plenty for us to work on."