C-class c200 lacking power

[kingsley1201]

Was driving my c-class c200 2.1 blue efficiency yesterday and after about 20 mins of driving on 60mph roads the car lost all power and wouldn't go over 20mph but no limp mode warning on the dash ? Thought it might be the turbo as I've had grey smoke from exhaust and a whining sound but that was since I changed oil cooler so don't think the sound is related but just wouldn't rev high and wouldn't go over 20mph for some reason. There's a pipe near the oil cooler what broke off but think that was before I did any work on it so I left it, would there be a pipe for the turbo or anything around the inlet side of the engine? Just wondering as it's cheaper to fix myself then get ripped off. Thanks kingsley