hello, I am boggled. I have a 760 turbo w/ 200k I've had about a year, the past owner overheated/blew head gasket, had headgasket replaced blah blah. It knocks at idle, disappears at about 1500rpm, and is the worst when the motor is at operating temp. After sitting all night at start up it is silent for a while and then appears. I thought piston slap for a while but all descriptions seem to describe it as worse when cold, disappearing when things warm up etc, dissconnecting fuel injectors alters the knock {probably more than one of the cylinders as the cause} depending on which is unhooked. the motor is great otherwise though, no smoke, little oil usage, good power, but the knock makes me think that the engine could take a shit at any time. any ideas????