Test NTC-4: Checking Engine Mechanical Systems

At this point, all engine electrical systems are operating properly and are not the cause of the driveability problem. Inspect the following items as possible causes:

• Engine vacuum must be at least 13 in. Hg in Neutral.
• Engine valve timing must be within specifications.
• Engine compression must be within specifications.
• Inspect camshaft lobes for abnormal wear.
• Check crankshaft slots for debris/damage.
• Engine exhaust system must be free of restrictions.
• Engine PCV system must flow freely.
• Engine drive sprockets must be properly positioned.
• Torque converter stall speed must be within specifications.
• Power brake booster no internal vacuum leaks.
• Fuel must not be contaminated.
• Fuel injector must not be plugged or restricted. Check that control wire is connected to proper injector.
• Check for related Technical Service Bulletins (TSBs) that may apply to the problem.

If coming to this test from an oxygen sensor test, and rich or lean condition is not corrected after checking items listed above, replace Powertrain Control Module (PCM). PCM is located to left of Power Distribution Center (PDC) in engine compartment. Road test vehicle and check for DTCs.