Symptom Checks

Check the following items:

• Check the following PID values: DPFEGR, LONGFT 1 and LONGFT 2. See appropriate PIN VOLTAGE/PID VALUE CHARTS article. On some models DPFEGR PID may not be applicable. If DPFEGR PID value is not within .15 volt of Key On Engine Off (KOEO) value, see TEST HE , step 100)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) 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 run lean.
• On Econoline 4.6L, Pickup 4.6L and Navigator 5.4L (4V) engine, also check IMTVF PID. Using scan tool, select IMTVF PID. Ensure transmission is in Park or Neutral. Note PID value when ignition switch is turned to OFF position and then in ON position. Start engine and raise engine speed to 3000 RPM. PID value should indicate NO in both situations. If either PID value indicates YES, see TEST HU , step 65)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
• Check fuel delivery system. See TEST HB (natural gas models) or TEST HC (except natural gas vehicles) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
• Check secondary ignition system. See TEST JB under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
• Check exhaust system. See TEST HF under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
• Check engine compression. Check engine mechanical condition and repair as necessary. Check intake manifold gasket, camshaft and valves. See appropriate article in ENGINES.
• On A/T models, if engine stalls during transaxle/transmission engagement, check A/T Torque Converter Clutch (TCC) solenoid or circuits. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
• Check for binding or dragging brakes. See appropriate article in BRAKES.
• On Mustang models, ensure A/C turns off under Wide Open Throttle (WOT) conditions. See A/C DOES NOT TURN OFF DURING WOT  symptom.
• On F150 Lightning Pickup (5.4L Supercharged) models, check supercharger bypass system operation. See TEST KJ under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article. Also on F150 Lightning Pickup (5.4L Supercharged) models, check secondary circuits used for high speed fuel pump operation. See TEST KA , step 70)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article.
• On M/T models, check clutch operation. On all models, check charging system. Check operation of Intake Manifold Runner Control (IMRC) or Intake Manifold Tuning Valve (IMTV), if equipped. 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 see TEST Z under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article and check for intermittent faults.