My 200 has developed a miss fire up at 6k to shift light. Took it to renault and came back as no errors etc. It sounds terrible like its dropping a cylinder on and off. Fine around town and below 5k. Odd, I always use vpower but the other day had to use 95 ron and it was worse. Only other thing it could be is I bought a ported thottle body could it be throttle related or coil pack? Help its killing me!