So did mine I thought mine might have been a stuck tappet, plus a few others have had horror stories about bits of cam that break off and either screw the turbo or mash the engine, either way I would check the cams anyway peace of mind, if its a stuck tappet you might be able to try some of that wynnes hydraulic lifter tappet additive people have said that it works and frees sticky tappets up, can't think what it's called but I'm sure someone will come along and tell you, it's deffo made by wynnes