What if your car engine had rough idle due to coolant entering the cylinders blown Head Gasket and you fixed the Gasket used Stop-Leak for repair but it still doesn't fire in all cylinders?

You cannot repair a blown head gasket with Stop-Leak. The head will have to be remove and a new gasket installed. Do not drive this car as serious engine damage will occur. I agree 100%. The head will have to come off and re-fitted with a new head gasket, and possibly exhaust and inlet gaskets as these tend to break if you have to remove the manifolds. Having the head "machine-skimmed" is also wise as it will ensure a gas tight seal between the engine block,head and gasket.I'm afraid that there is no way around this, if there were a bodge that could be done, I'd probably know about it!