What does an obstructed exhaust system lead to?

An obstructed exhaust system can lead to a loss of power in an engine because it creates back pressure that restricts the flow of exhaust gases. When exhaust gases cannot exit the engine efficiently, it becomes more difficult for the engine to draw in fresh air and fuel for combustion. This results in a decrease in engine performance, as the engine struggles to expel spent gases while maintaining the necessary intake cycle.

Moreover, the reduction in the engine's ability to breathe properly means that it cannot operate at its optimal efficiency, leading to an overall drop in power output. Therefore, the presence of restrictions or blockages in the exhaust system directly impacts the power available to drive the vehicle. The other options do not directly correlate to the effects of an obstructed exhaust system; for example, increased engine efficiency and low fuel consumption are typically seen in well-functioning systems, while improved engine cooling depends on proper exhaust flow rather than obstruction.