Econoline E350 1 Ton V8-5.4L Prop SOHC VIN Z (1998)
Idle Speed Air Control Valve (ISACV)
1.
Open the hood.
2.
Note:
Key symptom is elevated idle speed while noise is occurring.
Note:
"Snapping" the throttle can induce the noise.
Verify the condition by operating the vehicle for a short time.
3.
Inspect the ISACV. If physical evidence of contamination exists, install a new ISACV.
4.
While the noise is occurring, either place an EngineEAR probe near the ISACV and the inlet tube, or create a 6.35 mm (0.25 in)-12.7 mm (0.50 in)
air gap between the inlet tube and the clean air tube. If the ISACV is making the noise, install a new ISACV.
5.
Test the vehicle for normal operation.
Steering Gear Grunt/Shudder Test
1.
Start and run the vehicle to operating temperature.
2.
Set engine idle speed to 1200 rpm.
3.
CAUTION:
Do not hold the steering wheel against the stops for more than three to five seconds at a time. Damage to the power steering pump will occur.
