The above situations are normal conditions when the active eco system is activated to improve fuel efficiency.
Kia Cee'd JD Service Manual: Fuel Pressure Control Valve Repair procedures
Inspection
1.
Turn the ignition switch OFF and disconnect the battery negative (-)
cable.
2.
Disconnect the fuel pressure regulator valve connector.
3.
Measure resistance between the fuel pressure reg ...
Kia Cee'd JD Service Manual: Fuel Line Repair procedures
Removal
1.
Turn the ignition switch OFF, and then remove battery (-) cable.
2.
Release the residual pressure in fuel line.
(Reter to Fuel Delivery System - "Release Residual Pressure in Fuel
Line")
...