The throttle position sensor signal is stuck low. On the drive-by-wire 987 this can trigger limp / reduced power.
SYMPTOMS
- Check-engine light
- Reduced power / limp mode
- Erratic idle
- Poor throttle response
LIKELY CAUSES
- Failed throttle body/TPS
- Wiring short or open
- Connector fault
DIAGNOSIS STEPS
- Read TPS voltage vs pedal
- Check wiring
- Inspect/replace the throttle body
RELATED PARTS
- Throttle body (drive-by-wire)