P0303 on Saturn
Cylinder 3 Misfire Detected
P0303 on Saturn vehicles indicates cylinder 3 misfire detected. Au7o has documented this code across 2 Saturn models — most commonly on Aura, Vue. This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. Typical repair costs on Saturn range from $150 to $800, depending on the specific model and root cause.
Common Causes of P0303
- •Worn or fouled spark plug in cylinder 3
- •Failed or weak ignition coil on cylinder 3
- •Bad spark plug wire or boot (where applicable)
- •Clogged or leaking fuel injector for cylinder 3
- •Vacuum or intake air leak affecting that cylinder
- •Low compression (worn rings, burnt/leaking valve, head gasket)
- •Wiring or connector fault at the coil or injector
P0303 on Saturn by Model
Saturn Aura(1 issue)
- 3.6L Random/Multiple-Cylinder Misfire2007-2009
The 3.6L V6 Auras are reported to throw misfire codes, frequently as a downstream symptom of the stretched timing chains but also from worn ignition coils/spark plugs or carbon buildup on the direct-injection intake valves. Owners experience rough idle, hesitation, and a check engine light. P0300 with cylinder-specific misfire codes is common.
Saturn Vue(1 issue)
- V6 Valve Cover Gasket Oil Leak Soaking Coil Boots → Misfires2004-2007
On the 3.0L and 3.5L V6 Vue models, the valve cover gaskets become brittle and leak oil down into the spark plug tubes. The oil soaks the coil-on-plug boots, causing the rubber to swell and degrade so spark grounds out, producing misfires and rough running. Oil also drips onto the exhaust manifold, creating a burning-oil smell.
Looking for P0303 on a different make?
View P0303 across all makes →Frequently Asked Questions
What does P0303 mean on Saturn?▼
P0303 stands for "Cylinder 3 Misfire Detected." This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. On Saturn specifically, this code is documented across 2 models.
What causes P0303 on Saturn vehicles?▼
Common causes on Saturn: Worn or fouled spark plug in cylinder 3, Failed or weak ignition coil on cylinder 3, Bad spark plug wire or boot (where applicable), Clogged or leaking fuel injector for cylinder 3, Vacuum or intake air leak affecting that cylinder. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0303 on a Saturn?▼
Repair costs on Saturn range from $150 to $800, depending on the specific model and root cause.
Which Saturn models have P0303 documented?▼
Au7o has documented P0303 on 2 Saturn models: Aura, Vue.