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

Coolant leaking from intake manifolds is REAL common on GM truck engines. GM also has a big problem with mismatched injector flow rates that typically shows up at higher mileages. That can cause a lean misfire on one cylinder that you might not even be able to feel. That doesn't apply to the central injection system that sits near the throttle body. If you have individual injectors, switch two of them to see if the misfire goes to a different cylinder. If it does, the best fix is to buy a set of rebuilt injectors from a specialty shop. They will be flow-matched; something GM was too lazy to do on the assembly line. I'm only familiar with one shop in Indianapolis, owned by Jim Linder. They have a lot of very happy customers, mostly GM owners.

You said that already. Did you try switching two injectors to see if the misfire goes to a different cylinder? Can you even feel the misfire?

Would really be helpful to know the engine size when dealing with a running problem. The only listing I can find for a '96 Silverado is for a Canadian truck, and they don't show the injectors. Under the U.S. C1500, they show the central injection system. I've never had to work on one of those. It looks like you can remove two tubes and switch them to see if the misfire goes to a different cylinder.

Here's a photo from rockauto. Com to show what one injector looks like.