misfire problem

  1. #1
    i cant drive my car down the bypass or motorway so im having to go long way around places. it does start to misfire at 3500k- 4000k but when i reach that it mis fires. but so to say if i go past 60mph it will be on a constant misfire once ive stopped by the sound of it running of two not all four but when its colder out or im on a steep hill it does it at around 2000k so am i right in thinking this could be a coilpack issue or something more serious?
  2. #2
    Sounds like a coilpack to me, if it was an injector or spark plug it would do it in low revs not high