I have an 89 f250 with a 7.3 idi all stock.it is running really bad it smokes on idle and when u rev it alittle it has a bad clunk to it.it has no blow by its not eating antifreeze either. and ideas would be great..and u can heer a miss when u listen to the exhaust.u can just see the smaoke comin outa the stack in these picks and this is at idle.

 

My guess would be you have a injection pump or injectors laying down.

 

I would agree with a bad injector. How old are they?