Formula 1 needs to rediscover its "DNA", according to Renault boss Cyril Abiteboul.
The Frenchman says that in recent years, as the popularity of Formula E and the world endurance championship increased, the core message of F1 has become confused.
"We can't just mix it all up," Abiteboul told Speed Week.
"The life of the engine, the durability of tyres, the amount of fuel, this is for me no part of the formula one DNA.
"Le Mans was always about reliability, but grand prix racing should always be sprint racing from the lights to the flag."
However, Liberty Media is open to changes as it considers a big shake-up for 2021, and the aero rules are changing for 2019 to help spice up overtaking.
"We took care of the aerodynamics for 2019," Abiteboul said, "but important issues remain untouched.
"We have not talked about tyres. I understand that with a targeted degradation, the race should be exciting, but what does it mean if drivers have to save fuel?
"In my view, Formula 1 must be clear about what it represents for the fans. With hybrid technology we have breathed a modern wind but I do not understand what the real message is," he continued.
"We have a very good saying that to me applies in Formula 1 - you should never fix something that is not broken."
The current season continues next weekend in Monte Carlo.