Possible Cause & Correction

Check the following:

• Check fuel pump relay. Connect test light between fuel pump test terminal and ground or between fuel pump connector and ground. Turn ignition on. Light should illuminate for 2 seconds. If not, see FUEL PUMP RELAY in SYSTEM/COMP TESTS article. For location of fuel pump test connector, see COMPONENT LOCATIONS in SYSTEM/COMP TESTS article.
• Check for poor fuel quality or water contaminated fuel.
• Ensure TPS is not sticking or binding.
• Check EGR valve operation.
• Check for a leaking injector. Disconnect injector electrical connector at injector. Crank engine and watch for fuel leakage.
• Ensure coolant sensor circuit or coolant sensor resistance is not too high. See CODE 15 chart in TESTS W/CODES article or SENSOR RANGE CHARTS article.
• Check ignition system for a worn distributor shaft, bare or shorted wires, incorrect pick-up coil resistance, or loose ignition coil ground or moisture in distributor cap. Check for adequate spark using Spark Tester (ST-125).
• Check for shorts by spraying plug wires with a mist of water.
• Remove spark plugs. Check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits.
• Check for correct fuel pressure at all speeds.
• Check for a faulty in-tank fuel pump check valve. A faulty check valve will allow fuel in lines to drain back to tank after engine is stopped.
• Ensure correct PROM is installed in vehicle. Check with dealer for latest application information.
• Check for restricted exhaust system.