Recommended Procedure (Without Scan Tool)
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Ford RV Cutaway, 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, and 2003 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
- Ensure engine is at normal operating temperature. Disconnect MAP sensor hose at intake manifold. Install a "T" fitting between MAP sensor hose and hose nipple at manifold. Connect a 0-30 psi (0-207 kPa) gauge to "T" fitting. Ensure MAP sensor is connected for this test and that hose is long enough so gauge can be put inside cab of vehicle. See Fig 1 or Fig 2 .
- Road test vehicle up a hill or with vehicle fully loaded, with accelerator at wide open throttle. Note highest boost reading while accelerating through 2500-3000 RPM range. Boost level will level out after 3000 RPM. On Econoline, pressure (boost) reading should be 13 psi (90 kPa) or more. On Excursion and F250-550, pressure (boost) reading should be 16 psi (110 kPa) or more. On all models, if boost level is not okay, see POSSIBLE CAUSES .