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Saturn SC 1 P0302 Misfire: Code Shows Cylinder #2 but Actual Misfire is in Cylinder #1 - Diagnosis & Fixes

Model: Saturn SC 1 Fault Code: P0302 Posted: 2009-03-20 12:09

I own a 1996 Saturn SC 1 with SOHC engine, 165,000 miles, manual transmission. I'm experiencing a misfire code (P0302) that appears only during idle and disappears when driving—typically after reaching around 20 mph or shifting into second gear. The issue does not occur when the engine is revved while parked. The puzzling part: While the OBD-II system reports a P0302 misfire (cylinder #2), my actual testing shows that cylinder #1 is misfiring during idle. This discrepancy raises concerns about sensor wiring, mislabeling in scan tools, or faulty components. I've noticed a 2–3 mpg decrease on highways and reduced low-RPM power, which leads me to suspect a clogged or malfunctioning fuel injector for cylinder #1. I plan to remove and test that injector soon. However, I'd appreciate expert input—what could be causing this mismatch between the diagnostic code and actual misfire? I understand that older Saturn models are known for coil pack failures. Before replacing injectors, I'm considering checking the coil packs as a primary suspect. Are there individual sensors per cylinder on the Saturn SC 1? Is it possible that oxygen sensor wiring or installation order is incorrect? Could this be a timing-related issue? Any insights into how the engine identifies specific cylinders for misfire detection would be greatly appreciated.

Related fault codes
P0302
Comments (3)
Anonymous 2009-03-20 14:26

Are you relying on scan tool readings or actual cylinder cut-out tests to confirm which cylinder is misfiring? I've encountered aftermarket scan tools that incorrectly label cylinder numbers, even though they correctly identify the issue. Saturn SC models are known for coil pack failures—consider checking those before replacing injectors. Are your spark plugs and ignition wires in good condition?

Anonymous 2009-03-21 06:56

I conducted a manual cylinder cut-out test by removing each plug one at a time. If the engine doesn't drop RPM or runs roughly after removal, that confirms a misfire in that specific cylinder. Three different scan tools have consistently reported cylinder #2 as faulty. Based on this process of elimination: I've ruled out spark plugs and wires (both replaced and properly gapped). The only remaining possibilities are the coil pack or sensor wiring. While I suspect it's the coil pack—especially since it’s quite old—I’m still open to sensor issues. My best bet is a failing coil pack, which should be replaced regardless of current symptoms. Also, it's possible that oxygen sensors were installed in the wrong order during assembly.

Anonymous 2009-03-21 09:18

You're not alone—many Saturn SC owners have reported wiring errors between cylinders, especially with older models. I've seen this firsthand and it often leads to misdiagnosed codes like P0302 when the real issue is in a different cylinder.