Sunday, August 20, 2006

P0300 code (random misfire) for 1995 Grand Am 2.4L engine


Misfire code P0300 showed up in scanner accompanied by rough idle and lost of power. Spark plugs were checked and #3 is fuel fouled.

Basic Concept:

Aside from checking spark when top engine cover is removed (see picture), misfiring can be checked by measuring and comparing coil resistance and comparing them to each other.

Repair Strategy:

Before replacing any ignition parts, make a closer inspection of the coil boots and check for signs of crack. Contact ATS for TSB (service bulletin) regarding the engine oil pressure specs that can upset the valve openings of the cylinder head.


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