Having problems with acceleration, seems to accelerate normally to about half way down (pedal) then anything else seems flat with no response, even if i floor it it just doesnt seem to want to go over about 3000 revs, if i switch off then on again 5 mins later its fine for a couple of miles. also getting a kind of whooshing air noise which seems to be coming from behind glovebox when i accelerate hard. any ideas ?? ita a 1998 C250TD. await your helpfull responses as usual. cheers guys.