Honda Civic Owners Manual: Before Driving

Driving

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Driving Preparation

Check the following items before you start driving. ...

See also:

Honda Civic Service Manual. Cylinder Head Removal and Installation (R18A9)
1. Fuel Pressure - Relieving (Between the engine and the manual shut-off valve) (Natural Gas Model) Compressed natural gas is flammable and highly explosive. You could be killed or seriously injured if leaking natural gas is ignited. ...