300ZX Coupe V6-2960cc DOHC (VG30DE) (1994)
Fuel Filler Cap: Testing and Inspection
Fuel Filler Cap
1. Wipe valve housing clean.
2. Suck air through the cap. A slight resistance accompanied by valve clicks indicates that valve "A" is in good mechanical condition. Note also that,
by further sucking air, the resistance should disappear with valve clicks.
3. Blow air on the fuel tank side and ensure that continuity of air passage exists through valve "B".
4. If valve is clogged or if no resistance is felt, replace cap as an assembly.