My truck for the past few months on several occasions has tried to keep and idle after I turn the ignition key in the off position. Its only happened a few times but ever time it does it sits there and acts like its miss firing like just shaking fairly rough. how would something keep cranking without ignition from the plugs? and my key is off so there shouldn't be any power. my engine isn't hot either when it happens so I don't think its detonation.
That is dieseling. Happens when the idle is too high, fuel/air mix is too rich, timing not properly set. There are actually several things that can lead to that happening. I would start with checking the timing first then work your way to the carb. I know from experience these trucks can be very particular about where the timing is set.
Its getting spark from hot spots in the combustion chamber, may be carbon, tip of a spark plug, etc... But it should not do this. It is basically running by detonation only.
Are you saying the starter will not turn the engine over, it just clicks? Or does it even click when you try to start it? We are here to help each other, information is how we do that. We are not there, okay?