My 760 Turbo has suddenly experienced a power loss on high speed. She's running fine on low speed while no turbo push applied. Driving on a highway is difficult, she tends to slow down while I'm applying more gas and turbo push to her. Her indications are as follows: rev'ing high, turbo gauge needle pointing to approx. 1 o'clock position (varies with gas applied) and speed slows down as applied more gas. I've checked all vacuum hoses and turbo ducts/air hoses for leaks but nothing found. I even checked the inner part of the turbo assembly for foreign objects and the fan by turning it by hand which checked ok. Do I have a faulty turbo or something else. Any advise guys?