Pinpoint Test 2: Loss Of Power

PINPOINT TEST 2 - LOSS OF POWER

PINPOINT TEST 2	LOSS OF POWER
STEP	INSPECTION		ACTION
1	PERFORM VACUUM TEST Start the engine. Perform an intake manifold vacuum test. See ENGINE COMPONENT TESTS . Is the exhaust system OK?	Yes	See ENGINE SYMPTOM CHART for diagnosis and testing of the engine
1		No	Go to step 2
2	PERFORM VACUUM TEST - EXHAUST SYSTEM DISCONNECTED AT THE EXHAUST MANIFOLD Key OFF. Disconnect the exhaust system at the exhaust manifold. Start the engine. Perform an intake manifold vacuum test. See ENGINE COMPONENT TESTS . Is the exhaust system OK?	Yes	Go to step 3.
2		No	Go to step 4.
3	PERFORM VACUUM TEST - EXHAUST SYSTEM DISCONNECTED AT MUFFLER Key OFF. Reconnect the exhaust system at the exhaust manifold. See EXHAUST MANIFOLD in 2.5L 4-CYLINDER article in Engine (2.5L engine). See EXHAUST MANIFOLD in 3.0L V6 article in Engine . See EXHAUST MANIFOLDS in 4.0L V6 article in Engine . Disconnect the exhaust system at the muffler. Start the engine. Perform an intake manifold vacuum test. See ENGINE COMPONENT TESTS . Is the exhaust system OK?	Yes	Replace the muffler. Test the system for normal operation.
3		No	Replace the three-way catalytic converter. Test the system for normal operation.
4	CHECK THE EXHAUST MANIFOLD Key OFF. Reconnect the exhaust system at the muffler. Remove the exhaust manifold. See EXHAUST MANIFOLD in 2.5L 4-CYLINDER article in Engine for 2.5L engine. See EXHAUST MANIFOLD in 3.0L V6 article in Engine for 3.0L engine. See EXHAUST MANIFOLDS in 4.0L V6 article in Engine for 4.0L engine. Inspect the ports for casting flash. Is there casting flash present?	Yes	Remove the casting flash or replace the exhaust manifold. Test the system for normal operation. See EXHAUST MANIFOLD in 2.5L 4-CYLINDER article in Engine for 2.5L engine. See EXHAUST MANIFOLD in 3.0L V6 article in Engine for 3.0L engine. See EXHAUST MANIFOLDS in 4.0L V6 article in Engine .
4		No	See ENGINE SYMPTOM CHART for diagnosis and testing of the engine