Possible causes

– Faulty spark plug (s)
– Faulty ignition coil (s)
– Clogged or faulty fuel injector (s)
– Intake air leak
– Fuel injectors harness is open or shorted
– Fuel Injectors circuit poor electrical connection
– Ignition coils harness is open or shorted
– Ignition coils circuit poor electrical connection
– Insufficient cylinders compression
– Incorrect fuel pressure

Tech notes

The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”.

There is a factory service bulletin for the following Chevrolet models:

2000 Chevrolet S-10
2000-2008 Chevrolet Camaro
2000-2008 Chevrolet Lumina
2000-2008 Chevrolet Cavalier
2000-2003 Chevrolet Impala
2000-2003 Chevrolet Malibu
2000-2003 Chevrolet Monte Carlo
2000-2003 Chevrolet Silverado
2000-2003 Chevrolet Suburban
2000-2003 Chevrolet Tahoe
2000-2003 Chevrolet Venture
2001-2008 Chevrolet Express
2002-2008 Chevrolet Astro
2000-2003 Chevrolet Avalanche
2000-2003 Chevrolet Trailblazer
2003-2008 Chevrolet Blazer
2003-2008 Chevrolet S-10
2003-2008 Chevrolet Trailblazer EXT
2000-2008 Chevrolet Factory Service Bulletin OBDII Code P0300

When is the code detected?

The control module monitors the crankshaft speed and has detected a misfire condition

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Lack/loss of power
– Hard start
– Engine hesitation

P0300 CHEVROLET Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

CHEVROLET Technical Service Bulletins for P0300 code