What should a pilot monitor closely during an engine run-up before flight in the Warrior PA-28A?

During an engine run-up before flight in the Warrior PA-28A, monitoring the engine RPM and magneto drop is crucial for ensuring that the engine is functioning properly and safely. The run-up procedure involves checking the engine's performance by running it at a higher RPM to assess stability, responsiveness, and overall health.

Monitoring engine RPM allows the pilot to ensure that the engine operates within expected parameters during this pre-flight check. The magneto drop check is particularly important because it examines the functionality of the ignition system. A consistent drop in RPM when switching from one magneto to both indicates that the ignition system is working as intended. If there is an excessive drop or significant difference between the readings of the two magnetos, it could indicate a problem that requires attention before flight. Therefore, focusing on these metrics ensures the pilot can identify potential issues that might affect flight safety.

Other aspects such as cockpit temperature, noise levels, flight instruments, GPS settings, propeller condition, or cabin pressure, while important in their own right during various flight phases, do not directly pertain to ensuring the engine's proper functionality during the critical run-up phase. Hence, those checks are not the primary focus during this specific pre-flight procedure.