Missfires on #5 cylinder at idle and have a coolant leak at front of the engine at the top.

It probably does miss while driving, but happens so quickly you can't feel it. Bad wire, bad connection, wire shorting to manifold, bad compression.

Go and buy some cooling system leak detector dye and pour it into the system. The kit should come with a black light. Run the engine for about 30 minutes and use the included black light to look for the source of the leak.

The top of the engine on a Silverado is pretty big. The coolant could be leaking from the hose, thermostat housing, water pump, the intake, the block.

Follow the upper radiator hose to where it connects to a black metal tube behind the alternator. Follow the metal tube down to the engine. This is the thermostat housing. Is that where the leak is? If not, you'll have to either rent or borrow a pressure system tester from someplace like Autozone, Pep Boys, or Advanced and pressure test the system, or buy the leak detector kit I mentioned.