P0308 — Cylinder 8 Misfire Detected

P0308 means cylinder 8 is misfiring. On V8s with cylinder deactivation, a collapsed lifter is a frequent cause alongside the usual spark and fuel suspects.

Cost range: $50–$3,000. Severity: high. Safe to drive? No if flashing. A steady light means limit driving to a trip to the shop.

Most common causes of P0308

1. Worn spark plug — Always rule out first. ($20–$150)
2. Failed ignition coil — Swap-test to confirm. ($80–$350)
3. Collapsed AFM/DOD lifter — Known issue on GM 5.3L/6.2L engines — accompanied by ticking. ($1,200–$3,000)
4. Injector fault — Less common than ignition faults but worth testing. ($200–$700)

Symptoms drivers report with P0308

• Heavy vibration
• Ticking from one bank
• Flashing CEL
• Reduced power