umm i think u have have a few unrelated problems here, ur car should run just fine without the egr valve hoses connected u'll just throw an engine code after driving over a minute and a half once it notices its not connected, but ive never heard of a car idling weird because of it, id definitely say check all ur vacume hoses for leaks cracks weak points where the line may be caving in on itself stopping the vacume, umm.... what else to do.... are u throwing any codes off ur ecu? id say thats where id start to see if uve got something wrong, im not really familiar with ur newer car though so there may be someone else who is alot more knowledgable about this kind of thing who knows more about ur car. id say start from the beginning, check all ur basic maintainance things, spark plugs/plug wires/air filter/pcv valve/cap and rotor/these things all affect the way ur engine runs, often once we find the problems we have with our cars we realize that we replaced like 5 things that were probably fine to begin with. good luck