What is a common indication of an exhaust leak?

An exhaust leak can lead to several noticeable symptoms that affect a vehicle's performance and efficiency. One of the most common indications of an exhaust leak is unusual engine noise. This noise often presents as a loud hissing, popping, or tapping sound coming from the exhaust system, particularly when the engine is under load. Such sounds are typically due to exhaust gases escaping through cracks or holes.

In addition to noise, an exhaust leak can also contribute to decreased horsepower. When exhaust gases are not fully expelled from the engine, it can create back pressure that impairs engine performance, resulting in reduced power output.

Furthermore, an exhaust leak may lead to increased fuel consumption. Incomplete combustion and the need for the engine to work harder to compensate for the lost exhaust gases can result in higher fuel usage.

Since all these symptoms — unusual engine noise, decreased horsepower, and increased fuel consumption — are interrelated and can be attributed to an exhaust leak, it is accurate to say that they collectively indicate the presence of an exhaust leak. Thus, selecting "all of the above" encompasses the various effects that a leak can have on engine performance and efficiency.