DTC P0300, DTC P0301, DTC P0302, DTC P0303 Or DTC P0304: Condition

WARNING: This page is about a different car, the 2002 Suzuki Esteem. However, it is still accessible from the selected car via links, so may be relevant.

DTC will set when:

Engine is not running at high RPM.
Not being driven on a rough road.
RPM below a specified value.
MAP sensor changing rate is below specified value.
Throttle opening changing rate below a specified value.
ECM detects a misfire (misfire rate per 200 revolutions) which can cause overheating and damage to Three-Way Catalytic Converter (TWC).
When ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to TWC, but could cause exhaust emission deterioration.

ECM illuminates MIL after 2 drive cycles. Possible causes are:

Engine overheating.
Intake system vacuum leaks.
Secondary ignition system malfunction.
Incorrect fuel pressure.
Plugged or leaking fuel injector.
Incorrect engine compression.
Incorrect valve clearance.
Manifold Absolute Pressure (MAP) sensor malfunction.
Engine Coolant Temperature (ECT) sensor malfunction.
PCV valve malfunction.
EVAP control system malfunction.
EGR system malfunction.
Low fuel level.