ok the problem im having is that the truck runs and idles up and down until i unplug the map sensor or unhook the vaccum line to it. Then it idles fine and will run i dont understand the problem? Every sensor on the engine is new along with a new ecm and the head gasket was recently done idle air control is also new also the fuel pump is new. no vaccum leaks and good compression ive had several mechanics up here and none have figred it our yet. reallly need help.