What would cause a knocking noise when the engine is cold . What does a clicking or ticking sound mean when accelerating or releasing the gas pedal?

a "knocking" noise could be your lifters. and the ticking when accelerating and letting out of the gas is the same thing. check your oil and if it's full then you may need to think about either having them adjusted, or getting new ones. depending on what you have depends on whether or not you wanna sell it