What occurs if the manifold pressure is not decreased along with engine RPM under certain conditions?

If manifold pressure is not decreased along with engine RPM, it can lead to a condition known as "overboost," where the pressure in the intake manifold exceeds the design limits of the engine. This can happen particularly during operations such as rapid throttle advances or in high-load situations without proper adjustments to power settings.

When the manifold pressure remains high while the RPM is reduced, the engine can begin to run lean or detonate, which can place excessive stress on engine components. If these conditions persist, it could lead to overheating or mechanical failure, resulting in potential engine damage. Maintaining the appropriate balance between manifold pressure and engine RPM is critical for ensuring safe and efficient engine operation, preventing failures that could arise from excessive pressures or temperatures within the engine's system.