F 150 4WD Pickup V8-5.4L CNG VIN M (2001)
15. Remove the manual override tool from the fuel tank solenoid valve.
16. Install the fuel tank solenoid manual lockdown valve.
17. Turn in the manual lockdown valve jackscrew on the fuel tank solenoid valve.
18. Repeat the procedure until all affected tanks are vented.
Solenoid - Stuck Open