Engine Runs Rough Or Rolling Idle

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Mazda Tribute, 2003 Mazda Protege5, 2003 Mazda Protege, 2003 Mazda MX-5 Miata, and 2003 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

Check for air leakage from intake-air system parts.
Check for A/C system improper operation.
Check for spark plug malfunction.
Check for erratic signal to ignition coil.
Check for purge solenoid valve malfunction.
Check for improper operation of electronic throttle control system.
Check for EGR system malfunction.
Check for erratic or no signal from CMP sensor.
Check for low engine compression.
Check for improper valve timing.
Check for improper operation of valve timing control system.
Check for erratic signal from CKP sensor.
Check for poor fuel quality.
Check for PCV valve malfunction.
Check for air cleaner restriction.
Check for restriction in exhaust system.
Check for disconnected electrical connectors.
Check for inadequate fuel pressure.
Check for fuel pump mechanical malfunction.
Check for improper load signal input.
Check for fuel line restriction or clogging.
Check for improper operation or fuel injection control.
Check for fuel leakage from fuel injector.
Check for fuel injector clogging.
Check for engine overheating.
Check for vacuum leakage.
Check for pressure regulator malfunction.