Preliminary Checks
On A/T models, ensure gearshift is in Park. On M/T models, ensure clutch is fully depressed. Check battery connections. Check starter relay connections. Check alarm/anti-theft devices. Check fuses and fusible links. Check ignition switch.
Check for engine overheating. Check all wiring harness connectors. Check engine oil level and quality. Check Manifold Absolute Pressure (MAP) sensor hose. Check transmission Torque Converter Clutch (TCC) solenoid.
Check engine oil level. Check fuel quality. Check air restriction gauge located on air filter housing to determine if air cleaner needs replacement.
Check for binding or stuck accelerator pedal. Check for broken accelerator return spring.
Check wiring harness connectors. Check for restricted air intake system. Check for aerated engine oil. Check engine oil level and quality.
Check for binding or stuck accelerator pedal. Check for damaged accelerator return spring. Check if engine is operating at normal operating temperature.
RUNS ROUGH, MISSES, BUCK/JERK, HESITATION OR STUMBLES
Note. The Powertrain Control Module (PCM) is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined speed is exceeded.
Check for engine overheating. Check wiring harness connectors. Check engine oil level and quality. Check Manifold Absolute Pressure (MAP) sensor hose.
SURGE (ON ACCELERATION OR CRUISE)
Note. The Powertrain Control Module (PCM) is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined speed is exceeded.
Check engine oil level and quality. Check wiring harness connectors.
LOSS OF POWER/POOR FUEL ECONOMY
Note. The PCM is equipped with an RPM/speed limiting function that will shut off fuel delivery when predetermined speed is exceeded.
Verify symptom occurs under normal driving conditions without engine being under excessive load conditions. Check for binding/dragging brakes. Check wiring harness connectors. Check transmission and differential fluid.
Black Smoke
Perform the following
- Check Manifold Absolute Pressure (MAP) sensor hose for leaks.
- Check MAP sensor.
- Perform ENGINE PERFORMANCE DIAGNOSIS in the SYSTEM/COMPONENT TESTS - 7.3L DIESEL article.
- Check engine mechanical condition.
White Smoke (Water In Combustion)
Perform the following
- Perform GLOW PLUG SYSTEM OPERATION procedures in the SYSTEM/COMPONENT TESTS - 7.3L DIESEL article.
- Check engine mechanical condition. Check for cylinder head and intake manifold gasket leaks. Check for cracked/porous cylinder head and engine block.
- Check Manifold Absolute Pressure (MAP) sensor hose for leaks.
- Check MAP sensor.
- Perform ENGINE PERFORMANCE DIAGNOSIS in the SYSTEM/COMPONENT TESTS - 7.3L DIESEL article.
Preliminary Check
Check transmission fluid level and condition.
Check for external engine oil leaks. Check for proper oil dipstick. Check for proper oil viscosity.
Check for external engine oil leaks. Check for proper oil dipstick. Check for proper oil viscosity. Check if engine oil has been changed within 5000 miles.
Intermittent Simulation
To reproduce the conditions creating an intermittent fault, use the following methods
- Lightly vibrate component.
- Heat component.
- Wiggle or bend wiring harness.
- Spray component with water.
- Remove/apply vacuum source.
Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. See the TESTS W/CODES - 7.3L DIESEL article. Use test results to identify a faulty component or circuit.