Ford Expedition Stalling Issues

I have a 2005 Ford Expedition that had been running rough for a while mostly misfiring. I took it in and the mechanic stated new plugs were needed. It ran decent for a while until going in the shop again due to running rough. At that time we were told a new transmission was needed. Good thing the lady I bought it from had an extended warranty that transferred which covered most the cost. A while later the truck began acting up again with misfiring. Come to find out the original shop that changed our plugs did not put new boots in with them. Sometime later the truck began stalling so a dealership claimed it was the fuel pump so we had that replaced. It ran for a few weeks fine and began stalling again. This time we able to have a trustworthy mechanic look at it. After all the issues and several thousands of dollars the bottom line was the Powertrain Control Module (PCM) and most likely it was this all along and not the other so called issues. After $1600 for this latest fix it runs great. The down side is the dealership we took it to may not even have put in a new/used fuel pump. I guess that's what happens when you are stranded in the middle of nowhere and need a mechanic. You never know who to trust!