1996 Ford Explorer Owner's Manual - Page 96

Warning Lights and Gauges Some vehicles are equipped with an engine speed (RPM) limiting device contained within the Powertrain Control Module (PCM). The purpose of this device is to maintain peak engine speed (RPM) below a specified limit. This feature is only evident on automatic transmission vehicles when shifting manually (1, 2, D) and on all manual transmission units. (Engine speed limits may vary based on engine displacement.) If you are experiencing an "engine cut-out" condition at high speeds, it may be the result of this limiting device. It is a normal condition and can be avoided by reducing vehicle/engine speed. Tachometer NOTE: If the 4.0L engine exceeds 5200 RPM, the PCM will restrict fuel flow to maintain engine speed at or below 5200 RPM. This function is designed to protect the engine and should be considered normal operation. 95