P0455 2003 Infiniti G35 -

Question

Replaced sparkplugs disconnecting some vacume lines to remove these coils.engine then would not start.diconnected batt terminal with no results

Answer 1

Unfortunately there are many that can be wrong. The P0455 code is for an EVAP leak (e.g loose gas cap) and will not cause the no start situation. I suggest start by inspecting all the connector you disconnected during the spark plugs installation.