Coil pack on the way out?
Got a 2004 3.0 V6 petrol and when I accelerate to about 75mph and cruise on the motorway, my car judders a bit like it wont take any more, rather like a misfire, and my emissions light flashes on the dash. When I stop pressing on and let it settle down, at about 65-70mph, and cruise, the light eventually stops flashing and goes out, but as soon as I press on again it appears again and the juddering starts, like its misfiring again!
Could this be a coil on the way out?...Though if one was I'd have thought that the juddering misfiring feeling would be over the whole rev range and not just the higher band....3000+ rpm etc. Nothing is apparent at idle etc, it runs smoothly then!
It doesn't seem to do it when I accelerate hard, it seems to be in 4th gear or higher when I try to go faster.
Could it be that this is because when i'm accelerating harder, in the lower 2nd and 3rd gears, the coil is being forced to work, so to speak, and the extra load required to accelerate in the higher gear is causing a coil overload, or something like that.
Any ideas would be appreciated.