causing air leak perhaps? Had this happen to me after a plenum pull and displayed similar symptoms - car would start but would idle rough and eventually die. Removed the plenum again and discovered gasket was cockeyed and off center about 1/4" causing an air leak. See if you can keep the car running if you press the gas a little while it's idling. If it runs longer than before or keeps running than that could point to this as your problem. Good news if it is, as it's a simple fix. :-)