P0302 on Buick
Cylinder 2 Misfire Detected
P0302 on Buick vehicles indicates cylinder 2 misfire detected. Au7o has documented this code across 2 Buick models — most commonly on Lucerne, Regal. This code means the engine computer has detected a misfire specifically in cylinder 2, meaning that cylinder isn't completing combustion properly on some firing events. The computer watches tiny variations in crankshaft speed to spot when a cylinder fails to fire, and a misfire means the air-fuel mixture isn't igniting correctly — usually from a spark, fuel, or compression problem in that cylinder. You may feel a stumble, rough idle, shaking, loss of power, or a flashing check-engine light, and persistent misfires can damage the catalytic converter. Because it names a single cylinder, the fault is often a component serving just cylinder 2, like its coil, plug, or injector. Typical repair costs on Buick range from $400 to $7,500, depending on the specific model and root cause.
Common Causes of P0302
- •Worn or fouled spark plug (cylinder 2)
- •Failed ignition coil or coil-on-plug (cylinder 2)
- •Clogged or faulty fuel injector (cylinder 2)
- •Vacuum or intake air leak affecting that cylinder
- •Low compression (worn rings, burnt/bent valve, head gasket)
- •Damaged spark plug wire or boot (if equipped)
- •Carbon-tracked or cracked coil/plug causing spark loss
- •Faulty PCM/ECM driver (rare)
P0302 on Buick by Model
Buick Lucerne(1 issue)
- Lucerne Northstar V8 Head Bolt Pull / Coolant Loss2006-2011
The 4.6L Northstar V8 in 2006-2011 Lucerne CXS/Super (and STS, DTS, Cadillac SLS) is known for head-bolt thread pull from the aluminum block. Bolts back out of the block (rather than head gasket failing outright), allowing combustion gases into the coolant. Symptoms: coolant loss, white smoke, overheating, eventually no-start.
Buick Regal(1 issue)
- Carbon Buildup on Intake Valves (Direct Injection)2011-2017
Like other GM direct-injected engines, the Regal's 2.0T and 2.4L DI engines accumulate carbon deposits on the back of the intake valves because fuel no longer washes the valves clean. Over tens of thousands of miles this causes cold-start misfires, rough idle, hesitation, and reduced power and economy. It is a well-documented owner complaint on the turbo cars in particular.
Looking for P0302 on a different make?
View P0302 across all makes →Frequently Asked Questions
What does P0302 mean on Buick?▼
P0302 stands for "Cylinder 2 Misfire Detected." This code means the engine computer has detected a misfire specifically in cylinder 2, meaning that cylinder isn't completing combustion properly on some firing events. The computer watches tiny variations in crankshaft speed to spot when a cylinder fails to fire, and a misfire means the air-fuel mixture isn't igniting correctly — usually from a spark, fuel, or compression problem in that cylinder. You may feel a stumble, rough idle, shaking, loss of power, or a flashing check-engine light, and persistent misfires can damage the catalytic converter. Because it names a single cylinder, the fault is often a component serving just cylinder 2, like its coil, plug, or injector. On Buick specifically, this code is documented across 2 models.
What causes P0302 on Buick vehicles?▼
Common causes on Buick: Worn or fouled spark plug (cylinder 2), Failed ignition coil or coil-on-plug (cylinder 2), Clogged or faulty fuel injector (cylinder 2), Vacuum or intake air leak affecting that cylinder, Low compression (worn rings, burnt/bent valve, head gasket). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0302 on a Buick?▼
Repair costs on Buick range from $400 to $7,500, depending on the specific model and root cause.
Which Buick models have P0302 documented?▼
Au7o has documented P0302 on 2 Buick models: Lucerne, Regal.