2002 Mazda 626 Diagnostic Code P0300

CORRELL

MEMBER
2002 MAZDA 626
6 CYL
FWD
MANUAL
78,000 MILES

My engine hesitates under acceleration. The hesitation occurs only after the car has warmed up and is driven for 5-10 miles. The hesitation is most noticeable while accelerating in 2nd, 3rd, and 4th gear. The car was sitting for close to a year while I was deployed. The fuel in the tank when the symptoms surfaced was approximately seven months old. The MIL indicator did not light immediately. It took several cycles for the MIL to light. The MIL blinks when the hesitation is the worst. I used a DIY pocket scanner tool which displayed P0300. There are several possibilities but since the hesitation occurs only after the engine is at operating temperature, I suspect the ignition system (coil pack), CMP sensor, or the TPS.

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Hi correll, Welcome to 2carpros and TY for the donation

P0300 Random Misfires normally caused by vacuum leaks and contaminated fuel

For the hesitation inspect and test all the following listed below and get back with some testing results

Oxygen sensors.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard.