another 89 sundance stalling problem

i have the same basic problem as another individual who posted in this forum has. when reaching speeds around 50 mph or so, the car will simply loose RPMs and come to a stop. my father currently speculates that it is the fuel filter. i am aware that the problem could also have something to do with vapor lock, or the fuel pump circuit. he is old fashioned when it comes to cars and does not understand the way the code system works on cars newer than he worked on in his day... i myself am currently finding out how it works. he wants me to ask a simple question. when trying to determine weather or not the fuel filter is clogged, should it be relatively difficult for air to be blown into into the fuel filter if he were to use his mouth to blow through it? any further suggestions as to what the problem might be would also be very helpful... thankyou.