According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2003-2009 Nissan 350Z has 17 documented known issues, with 8 rated critical. The most serious are Crankshaft and Camshaft Position Sensor Solder Joint Failure — Stalling Without Warning (Recall 03V455000) ($0-$450 repair), Concentric Slave Cylinder (CSC) Failure — Clutch Pedal Drops to Floor (VQ35HR 6-Speed) ($900-$2,200 repair), Fuel Filler Hose Cracking and Leaking During Refueling (Recall 05V555000) ($0-$350 repair), Occupant Classification System Control Unit Varistor — Passenger Airbag Suppressed (Recall 08V521000) ($0-$900 repair), Fuel Pressure Damper Diaphragm Failure — Engine-Bay Ticking and Fuel Seepage ($100-$400 repair), NATS key-authentication no-start: lock mode or a key-read fault, Pre-Catalytic Converter Breakdown Sending Ceramic Debris Back Into the Cylinders (VQ35DE) ($800-$6,000 repair) and VQ35DE Rev-Up Engine Oil Consumption ($500-$3,000 repair). Across all issues with published estimates, repair costs range from $50 to $6,000. DIY maintenance guides at au7o.io.