Cars Technical Articles - Engine Misfire/Tick Noise, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0300 Set

Engine Misfire/Tick Noise, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0300 Set

- Edited: Sep 09, 2022
- Popularity: 112 Views



Vehicles Affected:

  • 2015-2019 Cadillac Escalade
  • 2016-2019 Cadillac CTS-V
  • 2014 Chevrolet Silverado 1500
  • 2014-2019 Chevrolet Corvette
  • 2015-2018 Chevrolet Silverado
  • 2015-2019 Chevrolet Suburban, Tahoe
  • 2016-2019 Chevrolet Camaro
  • 2019 Chevrolet Silverado LD
  • 2014 GMC Sierra 1500
  • 2015-2018 GMC Sierra
  • 2015-2019 GMC Yukon, Yukon XL
  • 2019 GMC Sierra Limited
  • Equipped with 5.3L Engine (RPO L83) or 6.2L Engine (RPO L86, LT1, LT4)


The Malfunction Indicator Lamp (MIL) ON and/or an engine misfire/tick noise. The DTC P0300 set or in history.


This may be caused by one of the following conditions:

  • Active fuel management (AFM) lifter that is mechanically collapsed and/or stuck all of the time.
  • Internal locking pin damage in the lifter, due to oil aeration.
  • A lifter has collapsed and is stuck in the lifter bore.
  • The engine may have a bent push rod.

  • Correction:

    Inspect the camshaft for damage while the lifters are removed from the engine. If damage is found, replace the camshaft.
    If service information diagnosis does not isolate the cause of this concern, the valve operation should be inspected.
    If the valve(s) are not moving, replace the valve lifter oil manifold and affected bank of AFM lifters.
    If the lifter has spun the bore, the guides should also be replaced.

    Service Procedure:

    There are two approved processes for removing the lifter when stuck in the bore:

    1. Use vice grips with a slide hammer.

    Engine Misfire/Tick Noise P0300

    Note: Be sure NOT to pry on the sealing surface of the block, as shown in the illustration below.

    Engine Misfire/Tick Noise P0300

    2. Use vice grips with a small pry bar.

    Typically, one of the above approved processes will remove the lifter that is stuck in the bore. If not, the engine will need to be replaced.
    With the lifter removed, be sure to inspect the bore for any damage. Typically, the lifter bores will look good with no indication of damage.