Thanks for the info.

I was betting on the shuttle valve being bad. I may be right.
What is all involved in a new FDM. The Ford shop said $194 to fix the problem. I'm mechanically inclined to do the work, but don't know what all is going to be rquired. I would bet on a new fuel pump.

I also understand that there has to be a new wiring harness installed too.

Thanks for the help!