whenever my truck is cold and i just start it and let it warm up, i have to keep my foot on the gas for a minute to make sure it doesnt die. well whenever i blip the gas softly when its cold like that(never going above 1500 rpm's) the engine makes a loud knocking sound that i do not know what it is.
hopefully its a rod trying to push its way through the side of the block
it wants to be replaced by new faster engine