Exhaust System Backpressure

Exhaust system can be checked with a vacuum gauge or a 0-5 psi pressure gauge. If a pressure gauge is used, remove O2 sensor. Connect gauge to O2 sensor port. Start engine, and run at 2500 RPM. If exhaust system backpressure is more than 2 psi, exhaust system or catalytic converter is plugged.

If a vacuum gauge is used, connect it to intake manifold vacuum. Start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge drops slowly after stabilizing, check exhaust system for a restriction.