Throttle body carbon fouling
- Symptoms
- Rough idle, hesitation, occasional stall
- Likely cause
- Carbon in throttle bore
- Fix
- Clean throttle body
- Applies to
- KGC10/KGC15/QNC10; Boon M300S/M301S/M310S (same platform)
- Related fault codes
- none
- Confidence
- unverified
Sources
Related problems on this car
- Misfire from coil / carbon
- Blocked catalytic converter
- A/C load: idle vibration & poor pick-up with A/C on
- Stalling at idle with A/C + brake, hard start
Similar problems on other cars
- Idle hunting / stalling when the clutch is pressed (IACV/throttle body) · Toyota Corolla (9th gen, E120)
- Lean code from an air leak (P0171) · Toyota Vitz (1st gen)
- Ignition coil-on-plug failure / misfire · Toyota Corolla (9th gen, E120)
Where the parts are · Warning lights · Fault codes · Maintenance
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Guidance only – confirm with a mechanic before repairs. All common problems