A Important Preliminary Checks

Before using this section, perform the Powertrain On-Board diagnostic (OBD) System Check to verify the following items:
^ The PCM and MIL (Service Engine Soon) are operating correctly.
^ There are no DTC(s) stored.
^ Ensure that the engine coolant temperature is not above 130°C (266°F). This will cause the PCM to operate in the Engine Metal Overtemp mode. While in this state, the PCM will turn OFF four cylinders at a time to prevent the engine coolant temperature from reaching damaging levels. Engine Metal Overtemp can be perceived as a lack of power, engine miss, or rough idle. If the engine is operating in the Engine Metal Overtemp mode, refer to DTC P1258. P1258
^ Scan tool data is within the normal operating range. Refer to Typical Scan Data Values.
^ Verify the customer's complaint to reference the correct symptom table.

VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful Visual/Physical check. It can lead to correcting a problem without further checks and can save valuable time. This check includes the following items:
^ PCM grounds for being clean, tight, and in the proper location.
^ Vacuum hoses for splits, kinks, and proper routing and connections. Refer to the Vehicle Emission Control Information label. Check thoroughly for any type of leak or restriction.
^ Intake air system for the following conditions:
- Dirty or damaged air cleaner element or housing.
- Damaged or collapsed intake air ducting.
- Poor intake air system connections.
^ Air leaks at the throttle body and/or intake manifold.
^ Throttle body contaminants or deposits.
^ Accelerator cable binding or damage.
^ Ignition system wiring for incorrect routing and/or poor connections.
^ System wiring for routing near high frequency devices (EMI condition).
^ Engine cooling system leaks. Refer to Engine Cooling.

Refer to the following Symptom tables:
^ Intermittent Conditions
^ Hard Start
^ Surges/Chuggles
^ Lack of Power Sluggishness, or Sponginess
^ Detonation/Spark Knock
^ Hesitation, Sag, Stumble
^ Cuts Out, Misses
^ Poor Fuel Economy
^ Poor Fuel Fill Quality
^ Rough, Unstable, or Incorrect Idle and Stalling
^ Dieseling, Run-On
^ Backfire