Stock top-mount intercooler heat soaks in traffic, cutting power.
Reviewed by SubaruReview Editorial Team · Last reviewed 2026-05-15 · Editorial standards
How this problem ranks against the other documented WRX / STI failures — cost, severity, and DIY difficulty at a glance.
| Problem | Years | Severity | Repair cost | DIY |
|---|---|---|---|---|
| WRX TMIC Heat Soak Power Loss (this page) | 2015-2021 | Minor | $0–$1,800 | 3/5 |
| EJ255/EJ257 Ringland Failure | 2008-2014 | Critical | $4,500–$8,500 | 5/5 |
| Boost Leak from Y-Pipe | 2002-2014 | Major | $150–$350 | 3/5 |
| Subaru WRX Turbo Banjo Bolt Screen Oil Starvation | 2002-2014 | Critical | $400–$2,500 | 4/5 |
This is one of several documented WRX / STI problems we track, and it fits inside the broader WRX & STI guide. If you're weighing repair against replacement, cross-check the Subaru repair-cost database and any open NHTSA recalls on your VIN before booking a shop.
Stock top-mount intercooler heat soaks in traffic, cutting power.
TMIC sits over hot turbo with limited airflow at low speeds.
TMIC sits over hot turbo with limited airflow at low speeds.
National average $0–$1,800.
Difficulty 3/5. FMIC conversion (Mishimoto, Process West) or upgraded TMIC + scoop.
Sluggish in traffic; Lower boost; Knock learned
Owners typically pay $0–$1,800 at an independent Subaru shop, parts and labor included. Our Subaru Head Gasket Replacement Cost guide breaks the job down by parts, labor hours, and where the money actually goes.
The same generation also sees EJ255/EJ257 Ringland Failure and Boost Leak from Y-Pipe. Both are documented with symptoms, cost, and a permanent-fix walkthrough — see the full list in the WRX / STI hub.
We rate it 3/5 on our DIY scale. Confident wrenchers can tackle it in a weekend using the permanent-fix steps above. Cross-reference the reliability & common problems hub for related jobs worth bundling while you're in there.
It's part of our Engine Guides cluster, which collects every article covering the same system as this failure.
Same failure mechanism documented on a different Subaru — shares components with this article.
Same failure mechanism documented on a different Subaru — shares components with this article.
EJ, FA, FB, and EZ boxer deep-dives — the engine background this failure sits inside.
Dig into the Problems Database to plan your next maintenance sprint, or browse every model hub for buyer's guides, generation breakdowns, and known-issue lists.