First post here, I bought a 2006 F150 5.4 XLT with 43,000 miles and have had it in the shop 5 times over the past 7,500 miles with the same problem. At 2000rpm and 50mph there's a violent misfire/jerk. They replaced the torque converter, all 8 coils, all 8 spark plugs, fixed a chip telling 4x4 to engage, and finally that #8 cylinder is dead and #4&#5 coils still not working. Should I let this garage work on the truck or trade it in. It's my primary vehicle and I'm running out of money working on it.

 

Take it to a good Ford dealer for a proper diagnosis.

 

I gave up on taking my rigs to none dealer shops long ago but I fix most stuff myself. If I can't do it it goes to the dealer. I've taken on some pretty big projects but there are some things I just cant or dont want to do. I found I end up spending more money at garages that dont have the proper training to work on that specific engine car/truck.
take glc's advice and take it in for diagnosis..

 

agreed. pretty much at this point man, you need to go to Ford....after the third time i would have questioned the shops abilities....bite the bullet and get that thing to a dealer.