I have a 97 E250 4X4 conversion van with a 5.4 and 115000 miles on it. The problem is: the engine stalls after the first start of the day, then it starts fine throughout the day until it sits overnight. I had this same problem at about 60000 mi, at which time the dealer replaced in tank fuel pump sending unit which solved the problem. This was after replacing the fuel filter etc. Then at 95000 mi. the same symptoms started up again so I checked the fuel pressure at the fuel rail ,30 psi which is what I usually runs at when everything is OK. I looked at the fuel tank pressure on a scanner and it was allways OK also. I allways hear the pump make it's wirring noise when I first turn the key on in the AM. I decided to change the fuel pump sending unit myself this time . Ford says you are supposed to replace the whole thing so that is what I did at the cost of about $300 for the part. They don't want to sell the pump separate from the sending unit for some reason. The problem went away just like the first time until now ,115000mi. The same thing is happening again.. the engine stalls after the first start of the day. I did find a kit at NAPA for just the fuel pump which will save some $. They want $ 160 for it.
The question is: should I be looking for something else with the fuel system that could be causing this same recurring problem? The fuel I use is the same as my wife's 5.4 f150 and no problems there. Any help would be appreciated.