You have to check the current draw on the fuel pumps. If your fuel pumps are bad they will draw to much and eventually fry the relay. Its a which came first the chicken or the egg scenario.

Check the fuel pumps first then you can safely say it is the relay.

Check this thread:
http://www.peachparts.com/shopforum/showthread.php?threadid=20307&highlight=current+fuel+pump