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PO302 Cylinder 2 Misfire with White Smoke and Strong Gas Odor - 2000 Oldsmobile Alero

Model: 2000 Alero Fault Code: P0302 Posted: 2012-12-07 12:51

I'm experiencing a cylinder 2 misfire on my 2000 Oldsmobile Alero, indicated by the diagnostic code PO302. When I start the car, it shakes noticeably and emits quick bursts of white smoke with a strong gasoline-like odor. The check engine light flashes intermittently but does not remain solidly on. The vehicle runs smoothly once I reach around 2 RPM, but performs poorly at idle. I'm unable to access the spark plugs due to their location beneath layers of debris in the Alero's engine bay, requiring specialized tools for inspection. Could this be a head gasket failure or an injector leak? Any guidance on diagnosing and fixing this issue would be greatly appreciated.

Related fault codes

P0302

Comments (6)

Anonymous 2012-12-07 14:55

Start by inspecting the #2 spark plug—check if it's wet, dry, black, tan, or white (indicating steam cleaning). Is there a noticeable coolant loss? Use a fuel pressure gauge and perform a leak-down test to evaluate for injector leaks. The strong odor may be gas-related; please describe the exact smell in more detail. Note: If replacing spark plugs during testing, use only AC DELCO plugs compatible with this model.

Anonymous 2012-12-07 23:21

A cylinder 2 misfire combined with white smoke strongly suggests a head gasket failure—this is a common issue in older Alero models and should be investigated promptly.

Anonymous 2012-12-08 11:53

The white smoke has a distinct gasoline smell. The car runs fine above 2 RPM, but shakes severely at idle. I cannot access the spark plugs due to their hidden location under debris in the Alero's engine compartment. Special tools are required for inspection. The specific fault code is PO302, and the check engine light flashes intermittently without staying on.

Anonymous 2012-12-08 13:39

Understood—diagnosing this can be challenging in practice. A flashing check engine light (CEL) increases urgency because it may indicate potential catalytic converter damage. Recommend performing a fuel pressure and leak-down test, along with inspecting the #2 spark plug. An injector leak is likely contributing to the misfire.

Anonymous 2012-12-10 18:06

What engine size do you have? If the smell resembles gasoline, has anyone tried removing the vacuum line from the fuel pressure regulator to check for leaks? This could be a key diagnostic step in identifying fuel system issues.

Anonymous 2012-12-15 15:35

It turned out to be a faulty ignition coil. Replacing the #2 coil resolved the misfire and eliminated the shaking at idle, with no further white smoke or odor reported after the repair.