2011 focus engine malfunction problem

[Barrettsthename]

My 2011 focus engine malfunction and power steering malfunction warning comes on after driving for a few minuites sometimes it stays on for a while sometimes it will be on for a few seconds there is no loss of power although it sometimes flashes up acceleration reduction, then if I turn the car off while it's on it won't restart the immobiliser kicks in if I rock the car it normally jolts something all warning lights go out and it will start. Anyone got any ideas on what it could be thanks