Exhaust System Backpressure
- Exhaust system backpressure can be checked with a vacuum or pressure gauge. If using a pressure gauge, remove oxygen sensor. Connect a 0-5 psi (0-0.35 kg/cm2 ) pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi (0.14 kg/cm2 ), exhaust system or catalytic converter is plugged.
- If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port. See Figure . Start engine and allow it to reach normal operating temperature. Observe vacuum gauge while opening throttle part way and holding steady. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.