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2004 AUDI A8

4.2L V8•AWD•AUTOMATIC•gas
1 active safety recall on this vehicle — view recalls
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P1340moderate severityPowertrain

Misfire Detected Crankshaft Segment Adaptive

on 2004 Audi A8 4.2L V8 · AWD

What this code means

The ECU detected a misfire through crankshaft speed variation analysis using its adaptive algorithm. The system has learned the normal crankshaft speed pattern and detected a deviation indicating cylinder misfires.

Symptoms

  • Check Engine Light
  • Rough running
  • Slight vibration at idle
  • Intermittent power loss

Common causes

  • Worn spark plugs
  • Failing ignition coil
  • Fuel injector issue
  • Compression loss on one cylinder
  • Engine mount masking vibration symptoms

Diagnostic steps

  1. Read misfire counters per cylinder
  2. Inspect spark plugs and ignition coils
  3. Test fuel injector balance
  4. Perform compression test
  5. Check engine mounts

Repair notes

Replace worn spark plugs and ignition coils; investigate further if misfires persist.

Other Powertrain codes on this vehicle

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