Rotten Egg Smell During Acceleration
A rotten egg smell (sulfur odor) when accelerating in a 2020 Subaru Outback typically indicates a failing catalytic converter or an overly rich fuel mixture causing the converter to overheat and emit hydrogen sulfide. This can also be caused by a contaminated fuel or a malfunctioning oxygen sensor.
Diagnosis Details
Possible Causes
Failing catalytic converter – internal contamination or overheating causing sulfur release.
Rich fuel mixture (faulty oxygen sensor, fuel injector leak, or MAF sensor issue) leading to excess unburned fuel in the exhaust.
Contaminated or low-quality fuel with high sulfur content.
Related OBD-II Codes
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What You Should Do
Have the catalytic converter and oxygen sensors inspected.
Check for diagnostic trouble codes (DTCs) related to catalyst efficiency or fuel trim.
If the smell is strong and persistent, replace the catalytic converter.
Also consider using top-tier fuel and ensuring the engine is properly tuned.
Related Repairs
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.
