i have a xts system and one of the 3015 phones keeps doing an intercom all call to the other phones, i have switched pairs, phones, positions, and still no luck, should i try switching out the card for a new one? or what?

Try this: Make sure that a 4/C line cord isn't being used for this phone. If it is, either disconnect the second pair from the jack or replace the cord with a 2/C one.

it was a 4 so i cahnged it to a 2 so we will see how it goes

Have you avoided the 636 station swap with all these changes? I have seen other problems follow the station number.