Performing NTC Mechanical Test
NOTE:
If coming to this test from oxygen sensor test and rich or lean condition is not corrected after checking items listed below, replace Powertrain Control Module (PCM). PCM is located under air cleaner.
At this point in diagnostic test procedure, all engine control systems have been determined to be operating as designed and not causing a driveability problem. Following additional items should be checked as possible causes:
- Check if any Technical Service Bulletins (TSBs) apply to vehicle.
- Check engine vacuum. It must be at least 13 in. Hg in Neutral.
- Check valve timing.
- Check engine compression.
- Check for exhaust system restriction.
- Ensure PCV system is functioning properly.
- Check camshaft and crankshaft sprockets.
- Check torque converter stall speed.
- Check power booster for internal vacuum leak.
- Check for fuel contamination.
- Ensure injector control wire is connected to correct fuel injector and injector is not plugged or restricted.