Jenson Button has admitted he is unsure whether the chronic tyre problems suffered by his Honda during the Australian Grand Prix can be solved.
AUSTRALIAN GP RESULT
1 F Alonso (Renault)
2 K Raikkonen (McLaren)
3 R Schumacher (Toyota)
4 N Heidfeld (BMW Sauber)
5 G Fisichella (Renault)
6 J Villeneuve (BMW Sauber)
7 R Barrichello (Honda)
8 S Speed (Toro Rosso)
Four safety car interventions left Button struggling for grip at the restarts and he finished 10th after blowing an engine on the last lap.
"It's a big issue and I don't know if we can solve it," said the Briton.
"It's a weakness we've had. We just can't get grip into our tyres. We need to do something for the next race."
Button, so confident after winning pole position for the third time in his career, managed to hold off eventual winner Fernando Alonso at the start.
But his problems started during the first of four safety car interruptions, after Felipe Massa's Ferrari, Christian Klien's Red Bull and Nico Rosberg's Williams clashed at the first corner.
"I got off the line to keep Fernando behind me and at that point the car was driveable," said Button.
"But as soon as the safety car came out we were screwed as the tyres lost their temperature. We were on a soft tyre and I was losing four seconds a lap.
"At the restart the grip went, the car started shuddering and they all came past me for about four laps."
Button did well to maintain fifth place until the final lap, but his Honda engine failed in a cloud of smoke and flame within sight of the finish.
"The engine started to go a couple of corners earlier and going into the last I heard it go," said the 26-year-old.
"We've got a car that's quick over one lap in qualifying but as soon as the tyre temperature drops we simply don't have the grip.
"I pulled off onto the right hand side, it wouldn't have reached the finish line."
Honda team boss Nick Fry was equally frustrated, particularly as team- mate Rubens Barrichello had battled through the field from 16th on the grid to sixth.
"We had great trouble getting heat into our tyres, especially the front tyres. He (Button) is less than impressed, but rightly so," said Fry.
However, he contradicted Button's version of events and said the team opted to forego the possibility of points and instructed the driver to pull over before the finish to avoid an engine penalty at the San Marino Grand Prix at Imola on 23 April.
Engines have to last for two races, and drivers are penalised 10 places on the grid if they are changed before that unless they fail to finish a Grand Prix.
"It was a quick call by the race engineer and we need to see if it was right later," Fry said.
"We've got some improvements to the car for Imola but this was an unexpected problem and we're going to have to sit down with Michelin and sort it out."