Chevrolet Repair: Black Smoke upon starting, piston rings, clatter

Question
1995 350 siverado pickup . does not start as easily as usual and smokes black upon initial start. has 100k mi. plugs changed appr. 8 months ago but recently I changed rotor , contact was completely gone. Truck would turn over but hard to start. Now the black smoke and hear clatter of valves like when using cheap gas. We use premium. Could it be the plugs? (oil is changed every 3k to 4k miles, burns very little oil) Could use some direction
Thanks Freddie-Texas  

Answer
Sounds like you have leaking injectors as the vehicle sits overnight.

That would explain the black smoke and the clatter is most likely spark knock from the gas washing the oil from the piston walls and piston rings, Which also causes the engine oil to become THINEED out thus your oil usage.


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