Visual Check
WARNING: This page is about a different car, the 1995 Ford Explorer and 1995 Ford Aerostar. However, it is still accessible from the selected car via links, so may be relevant.
Complete all steps in BASIC TESTING - 4.0L article in the ENGINE PERFORMANCE section before proceeding to self-diagnostic tests. Ensure all vacuum hoses and EEC-IV wiring harnesses are properly connected.