Right first of all I suspect a head gasket is on it's way out although there's no sign of yoghurt as I did an oil change yesterday. This started a few weeks ago but this morning I noticed it the most, it only happened in 3rd gear today but I put my foot down after shifting into 3rd and I can hear my engine rev up but it isn't in timing with the speedo or rev counter, it'll still be at like 3000 but it sounds as thought it's more at 4 or 5000 then after a good few seconds it will start to catch up on it's self so the engin speed is in time with the clock. Any idea what could be the problem? Blocked fuel filter - not getting enough fuel? Head gasket on it's way out? Any help would be appreciated Thanks