2005 Ford Taurus 3.0L P0301 and P0456: Rough Idle, Poor Acceleration, and Misfire Diagnosis

Hi everyone, I'm new to this forum and really appreciate the community's help. I own a 2005 Ford Taurus with 150,000 miles. About 3,000 miles ago, I replaced the spark plugs, distributor, and plug wires. Recently, while driving my friend to another town for job applications, I noticed an immediate and severe engine misfire as soon as I started the car. The vibration was strong enough that I could feel it through the floorboard. Within four minutes of starting, the check engine light illuminated. Using a torque app and Bluetooth OBD-II scanner, I retrieved fault codes: P0301 (Random Cylinder Misfire - Cylinder 1) and P045-6 (Evaporative Emission System Leak Detected). The car now runs extremely poorly—lacking power and producing a noticeable misfire in the exhaust sound. I've already checked the fuel cap and filler tube, both of which appear to be intact and properly sealed. I'm looking for reliable troubleshooting steps. While random cylinder misfires are common in this model, the presence of P0301 specifically—combined with severe idle and acceleration issues—suggests a deeper problem. I suspect it might not be a vacuum leak affecting all cylinders, as that would typically cause broader performance problems. What should I check next? Any insights or suggestions for diagnosing this issue would be greatly appreciated.