What is a common consequence of dirty intercoolers?

Dirty intercoolers can lead to excessive power consumption due to the way they affect the engine's efficiency. An intercooler is responsible for cooling the air that comes from the turbocharger before it enters the engine's intake manifold. When an intercooler is dirty, it becomes less effective at transferring heat from the compressed air, which means that the air entering the engine is not as cool and dense as it should be.

Engine performance relies on having a higher density of air for combustion. If the intercooler is contaminated, there’s a significant drop in the air charge density, leading the engine management system to compensate by increasing the amount of fuel injected to maintain performance. This results in more fuel being consumed, hence excessive power consumption. With the engine working harder to produce the same power, it ultimately can lead not just to inefficient fuel usage but also potential overheating issues if not addressed.

The other options do not align with this outcome; increased fuel efficiency and improved air quality are unlikely when an intercooler is dirty, and decreased power consumption is not a typical result of this situation.