Problems/WRX / STI/WRX TMIC Heat Soak Power Loss
    MinorAffects 2015-2021

    WRX TMIC Heat Soak Power Loss

    Stock top-mount intercooler heat soaks in traffic, cutting power.

    Last updated: 2026-05-15

    Repair cost
    $0–$1,800
    DIY difficulty
    3 / 5
    Severity
    Minor
    Annoying or cosmetic — schedule when convenient
    Affected
    2015-2021
    Top-mount intercooler, Intake

    What goes wrong

    Stock top-mount intercooler heat soaks in traffic, cutting power.

    Symptoms to watch for

    • Sluggish in traffic
    • Lower boost
    • Knock learned

    Root cause

    TMIC sits over hot turbo with limited airflow at low speeds.

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    Buy time with these

    • Hood vent scoop water spray
    • Avoid extended idle after spirited driving

    Permanent fix

    1. FMIC conversion (Mishimoto, Process West) or upgraded TMIC + scoop.

    FAQ

    What causes wrx tmic heat soak power loss?

    TMIC sits over hot turbo with limited airflow at low speeds.

    How much does it cost to fix?

    National average $0–$1,800.

    Is this a DIY repair?

    Difficulty 3/5. FMIC conversion (Mishimoto, Process West) or upgraded TMIC + scoop.

    What are the symptoms?

    Sluggish in traffic; Lower boost; Knock learned

    Sources

    • NHTSA
    • Subaru Owner Forums

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