Get your DTC'* pulled at Autozone. Tell us what the codes are and we can walk you through fixing it.
When did you last change spark plugs? spark plug wires? fuel filter?
Start with checking your plug wires and coils:
Switch the coil pack for cylinder 3 with one of the other coil packs, and determine if the misfire moves with the coil. If it does, the coil is bad.
If the plugs, wires, and coils are all okay we will check your injectors next.
Let us know what you find.