fuel pump 280SE 1977
 

Replaced the pump & filter less than a year ago. It now stops pumping intermittantly. It occurs most often when the car is shut off, sets for an hour or more. Cannot restart but if I let it sit for 4 to 5 hours it will sometimes restart. Is this a faulty pump or an a relay that comntrols the signal to the pump? Today whem it wouldn't start I disconnected the output line from the pump and no fuel was pumping. All of a sudden it started pumping. Put it back together and it would not start.