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DTC P0300/16684 - Random Misfire Detected

NOTE: DTC is set when misfiring has been recognized in more than one cylinder. If misfiring rate is low, MIL is lit after 2 successive trips without a preceding cold start with a malfunction occurring. If misfiring rate is high, MIL will immediately start blinking. Damage to 3-way catalyst is possible. Repair malfunction as soon as possible.
  1. If DTC P1250/17658 FUEL LEVEL TOO LOW is also set in memory, this indicates there is less than 3.2 gallons of fuel in tank. Check fuel tank level and fill if necessary. If fuel level is okay, go to next step. If fuel level was low, erase DTC memory. See procedures under CLEARING CODES  . Test drive vehicle. See TEST DRIVE. If DTC P1250/17658 FUEL LEVEL TOO LOW is not set in memory, go to next step.
  2. If other DTCs are stored, (i.e. fuel injector, HO2S, fuel system, etc.) these stored DTCs may cause misfire. Repair other DTCs as necessary. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  3. If misfiring has been recognized for several or all cylinders, go to step 5). If misfiring has been recognized on 2 cylinders (i.e., 2 and 4, 3 and 5, 1 and 6), go to next step. If misfiring has only been recognized on one cylinder (i.e. 2 or 4, 3 or 5, 1 or 6), check ignition wiring harness, spark plug cables and fuel injectors for cylinder(s) which are faulty. For fuel injector testing, see FUEL INJECTOR TEST in the BASIC TESTING article. Repair as necessary. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE. If no other DTCs are stored, go to next step.
  4. Inspect ignition coil for affected cylinders. See IGNITION COIL in the BASIC TESTING article. Repair as necessary. If vehicle was not repaired, go to next step. If vehicle was repaired, erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  5. Inspect air intake system for a leak. Repair as necessary. If an intake leak was not found, go to next step. If an intake leak was repaired, erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  6. Inspect fuel pump and residual fuel pressure. See FUEL PUMP PERFORMANCE  table. Repair as necessary. If components are okay, go to next step. If a malfunction was repaired, erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  7. Check EGR valve and system components. EGR flow may be too high. Inspect hoses, etc. Repair as necessary. If EGR system is okay, go to next step. If EGR system was repaired, erase DTC memory. See procedures under CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  8. Inspect fuel injectors for carbon deposits. Replace as necessary. If fuel injectors are okay, go to next step. If fuel injectors were replaced, erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  9. Inspect intake valves for carbon deposits. Clean as necessary. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
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