4.3 Vortec V6 started missing with loss of power. Replaced all engine gaskets including, intake, head, and exhaust gaskets. Found lower intake gaskets broken and damaged. Replaced plugs, wires, and distributor cap. Engine no longer leaks but continues to miss with loss of power. I smelled the faint smell of antfreeze for sometime and noticed a grey sludge on the oil filler cap before replacing gaskets. Could this leak have caused damage to the fuel injectors?