Recommended Procedure:

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2004 Ford RV Cutaway, 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, and 2004 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The engine must be at operating temperature.

Connect the scan tool.
Key on, engine running.
Access and monitor the IPR and RPM PIDS.
Operate the engine at low idle speed.

If the IPR duty cycle is less than the MAX specification, go to the next step. If the IPR duty cycle is greater than the MAX specification, go to Test 10e of the Hard Start/No Start Diagnostics and check for an injection control system leak.