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Home >> Ford >> 1988 >> Bronco II 4WD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> EEC-IV CEC System >> Quick Test >> Intermittent Erratic Running Or Rough Idle
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Intermittent Erratic Running Or Rough Idle

  1. Check color at top of fuel injectors to ensure correct application. Check distributor cap, plug firing voltages, cylinder balance, and base ignition timing.
  2. Check spark plugs for fouling and proper gap, cylinder compression, and engine/valve train operation. Check Thick Film Integrated (TFI) ignition module, Profile Ignition Pick-Up (PIP), and coil.
  3. Check Spark Output (SPOUT) connector. Connect Manifold Absolute Pressure (MAP)/Barometric Pressure (BS) tester to MAP or BP sensor (depending on vehicle). Check readings with engine off and with ignition switch in "ON" position. Compare reading with MAP/BP SPECIFICATIONS  table.
  4. Repeat MAP test with engine running. Reading should decrease at idle and increase when throttle is opened. On MAP sensor equipped vehicles, if readings with engine off and ignition on do not match values given, go to TEST B6  , MANIFOLD ABSOLUTE PRESSURE (MAP)/BAROMETRIC PRESSURE (BP) SENSOR test.
  5. If MAP sensor does not change when throttle is opened (engine running), substitute a known good vacuum hose at sensor and repeat test. On vehicles equipped with either MAP or BP sensors, substitute sensor(s) and retest.
  6. On Vane Airflow Meter (VAF) equipped vehicles, check for unmetered air leaks. Using breakout box, monitor VAF signal while manually moving vane door. Voltage must smoothly increase as door is opened.
  7. Using Fuel Injector Tester/Cleaner (Rotunda 113-00001), check flow of injectors.
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