The reason I asked about the filter and cap on the secondary (fuel bowl filter and cap) is important.

You said " I have no reason to believe it's not original". Never go with your beliefs on a second owner truck or any other vehicle.

Aftermarket caps have been floating around for many years. The problems that go with them have too.

If the cap is slightly taller than OEM, and you use an OEM motorcraft filter, it won't compress the plunger in the fuel bowl to the correct level. Meaning that the fuel will vacate the bowl via gravity and introduce no starts or hard starts, air in system.

For what your going thru and the cost of an OEM cap. Just get one so you can sleep.

Every month I drain my primary in a glass jar and let it settle overnight for inspection of water/debris. I cycle the key for 20 seconds 8-10 times and have never had a problem with air.

Just sayin

Denny

 

I had a bad fuel filter oring and or fuel filter. And yes they were motocraft. I must have gotten a dud. I went into town yesterday morning got another set of filters and changed them. One last ditch effort before calling in someone with more expertise than me. I only changed the upper filter and it's oring. I figured I would try just that one before doing the harder one under the truck. After bleeding the fuel for 10 minutes using Forscan, the truck cranked right up and has not missed a beat.

 

Attaboy!

Denny