2008–2021 Subaru WRX STI: Misfire, smoke or engine failure (EJ257 ringland/piston failure)
Likely causes, ranked
- Cracked piston ringland (often cylinder 4)$4,000–$7,000Shop
- Rod bearing failure from oil starvationShop
- Lean condition or fuel pressure fault under boostShop
Real-owner fix counts will appear here as reports come in.
Rough cost: $4,000–$7,000DIY or shop: See DIY or shop section
Parts to check
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Symptom: A misfire on one cylinder, blue or white smoke, oil consumption, low compression on one cylinder, or a knock.
Likely causes
- Ringland failure. IW STI forum tuners describe the cast pistons in the EJ257 cracking between the ring grooves, sometimes even on stock cars, and much more often when tuned.
- Rod bearing. r/WRX owners report rod knock failures and link them to oil starvation.
Rough cost range
| Repair | Reported |
|---|---|
| Short block / engine repair | Roughly $4,000–$7,000 (RepairVerdict); more if damage spreads |
DIY or shop?
Shop. Do a compression and leak-down test first.
Useful steps
- Do a compression and leak-down test if you have a misfire.
- Keep the oil level full.
- Use a reputable tuner, or stay stock.
Vehicle focus: 2008–2021 Subaru WRX STI.
Safety / mechanic note
A failing piston can lead to sudden engine failure. Verify with a mechanic.
Recalls & service bulletins
No recalls or service bulletins are listed for this page yet.
NHTSA complaints: Count unavailable: NHTSA files some model years in this range under shared or missing model names, so a model-specific count isn't possible (checked 2026-10-15).
Always check your VIN for open recalls at nhtsa.gov/recalls.
Sources
What actually fixed it?
Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.