1998 Ford Maverick loss of power

Hi just aquired this motor with the following fault, starts from cold and runs through the rev range for about ten mins, but when warm will not rev and misses and plumes of white smoke from exhaust. Could be turbo, erg valve, fuel pump??????? any guidance as to the fix of this problem before I go throwing money at the nearest ford dealer would be appreciated. the previous owner mentioned a fault code 34 which he said was a knock sensor?. Many thanks in advance. Dickiedewalt