i have a smart passion. nice little car, but the last few days its giving me trouble. its got all the power when i drive until i reach 90km/h then it loses power and i can only drive 30km/h. evan if i restart the car it has no power. i must first disconect the battery for a few sec then the car has its power back. but just as long as i drive under 90km/h. can anyone please help me?