Symptom Checks

Check the following items:

• Check the following Parameter Identification (PID) values: DPFEGR, LONGFT 1 and LONGFT 2. See PIN VOLTAGE/PID VALUE CHARTS article. On some models DPFEGR PID may not be applicable. If DPFEGR PID voltage is not .2-1.3 volt with Key On Engine Off (KOEO), go to TEST HE, step 100) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article. If LONGFT 1 or LONGFT 2 PID value is low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT 1 or LONGFT 2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to lean.
• On Econoline 4.6L, Explorer 4.0L SOHC, Mountaineer 4.0L SOHC, Pickup 4.6L and all models with a 5.4L engine, also check IMTVF PID. Using scan tool, select IMTVF PID. Turn ignition on and note PID value. Start engine and raise engine speed to 3000 RPM. Again, note PID value. If either PID value indicates YES, go to TEST HU, step 65) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
• Check fuel delivery system. See TEST HB (natural gas vehicles) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
• Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
• Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
• Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
• On A/T models, ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See appropriate article in AUTOMATIC TRANSMISSIONS.
• Check for binding/dragging brakes.
• On Contour, Cougar, Econoline 4.2L, Mustang and Mystique, check if A/C turns off under Wide Open Throttle (WOT) conditions. See A/C DOES NOT TURN OFF DURING WOT  symptom.
• On F150 Lightning Pickup and Super-Duty Pickup models, check secondary circuits used for high speed fuel pump operation. See TEST KA, step 70) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article.
• On M/T models, check clutch operation. On all models, check charging system. Check customer driving habits (i.e., driving with excessive loads). If no problems are indicated, return to SYMPTOM DIAGNOSIS  to identify any additional symptoms or go to TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V article and check for intermittent faults.