2006 Pathfinder P0030 Code: Misfire and Shaking at Idle - Diagnosis and Fixes

I own a 2006 Nissan Pathfinder and recently started experiencing severe shaking while idling, especially at traffic lights. The service engine light activated shortly after. I took it to an auto parts store for OBD2 scanning, which initially showed a faulty coil pack for cylinder #1. Replacing the coil with a used unit seemed to resolve the issue temporarily. However, after driving about one mile to reach the auto parts store (where I accidentally damaged the battery terminal while reconnecting the battery), the vehicle began to shake again during deceleration at a traffic light. The engine sounded like it had a clogged exhaust, and when attempting to accelerate, it struggled—losing power on a small incline. Flooring the gas pedal resulted in a bogging effect; the engine would only reach around 1500 RPMs, then start 'ramping' up to about 2500 RPMs before stalling. A coworker used a diagnostic scanner and found code P0030. He then performed individual coil testing by manually disabling each coil via the diagnostic computer. The #1 cylinder coil did not respond when disabled, suggesting it may be faulty or improperly connected. I replaced the coil with a new one, but the problem persists. I am now unsure whether this is a sensor issue, wiring fault, or a deeper misfire condition involving multiple cylinders (cylinders 1, 3, and 5 were mentioned in earlier reports). The presence of both P0030 and P0300 suggests ongoing misfires. I'm seeking advice on next steps—should I consider replacing the oxygen sensor, checking the fuel system, or investigating wiring harnesses? Any insights would be greatly appreciated.