Test NTC-4: Checking Engine Mechanical Systems

At this point in diagnostic test procedure, all engine electrical control systems have been determined to be operating as designed and not causing a driveability problem.
On 4.7L, go to next step. On 5.2L and 5.9L, distributor must be check for proper position. Connect scan tool to DLC. Using scan tool in MISCELLANEOUS FUNCTIONS, choose SET SYNC. The SET SYNC will indicate position of distributor for fuel synchronization, not the ignition timing, as ignition timing is controlled by Powertrain Control Module (PCM). Follow instructions on scan tool and start engine. Warm engine to normal operating temperature and note display on scan tool with engine idling. If IN RANGE with zero degrees is displayed, go to next step. If a plus or minus number is displayed next to the degree number, distributor must be repositioned. Loosen distributor clamp retaining bolt. Rotate distributor until IN RANGE is displayed on scan tool. Continue rotating distributor until achieving as close to zero degrees as possible. Tighten distributor clamp bolt to 16 ft. lbs. (22 N.m). Once distributor is properly positioned, go to next step.
On all models, following additional items should be checked as possible causes:
- Check engine vacuum. Engine vacuum must be at least 13 in. Hg with transmission in Neutral.
- Check engine valve timing.
- Check engine compression.
- Check exhaust system for restrictions.
- Ensure PCV system is functioning properly.
- Check torque converter stall speed (A/T models).
- Check power brake booster for internal vacuum leak.
- Check fuel for contamination.
- Ensure proper fuel injector driver wiring is installed on correct fuel injector. Ensure fuel injector is not plugged or restricted.
If none of the problems listed exist, test is complete. If any of the problems listed exist, repair as necessary. Perform TEST VER-2 .