04 trailblazer misfire

You have the I6 engine? There are no plug wires. A couple of things here....1. Triple check the coil is seated correctly on #4, listen and feel for the click. 2. The hood seal is defective on our platform. Will let water in and can/will fill the plug hole with water, specifically cylinder #4. Although, I've had water in #4,5, and 6. Use a mirror to look down the hole. If you see water, dry it out. Rag wrapped around a long screw driver is what I use. Then use a self adhesive weather stripping and run it along the metal lip in front of the stock hood seal. 3. Look down the plug hole if you see oil, that could also cause a misfire, you're looking at a new valve cover gasket.