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Home >> GMC >> 1987 >> Forward Control 6.2 J, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - TBI >> Trouble Shooting >> Cuts Out Or Misses
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Cuts Out Or Misses

  1. Check for a cylinder that misses by disconnecting IAC motor. Start engine. Using insulated pliers, remove spark plug wires one at a time. If there is an RPM drop on all cylinders, see ROUGH, UNSTABLE, INCORRECT IDLE OR STALLING . Reconnect IAC motor.
  2. If there is no RPM drop on one or more cylinders, check spark at suspected cylinder(s). If there is no spark, check ignition system. If there is spark, remove and inspect spark plugs.
  3. Check fuel filter for restrictions. Check fuel for water contamination. Check fuel pressure. See FUEL SYSTEM PRESSURE TEST . If okay, check engine for mechanical defects (worn rocker arms, broken valve springs, etc.).