What can be used to check for a restricted exhaust system?

To check for a restricted exhaust system, you can use a vacuum gauge to measure back pressure in the exhaust system; a reading above the manufacturer's specifications indicates a restriction. Additionally, observing engine performance issues such as decreased power, poor fuel efficiency, or unusual noises can signal exhaust blockage. A visual inspection of the exhaust components for dents, rust, or damage can also help identify restrictions. Lastly, performing a "free rev" test—observing how the engine revs without load—can indicate exhaust flow issues if the engine struggles to accelerate.