I have a 2006 F250 6.0l. It has been starting great then one day last week it would not start (spin over no start) after driving parked it and when a came back it would not start. Had it towed to dealer they replaced the FICM and the EGR valve. Two days later same thing would not start after driving and stopping. Towed back to dealer now they say the batteries need to be replaced. This does not make sense to me. Should they have checked the batteries in the beginning? Please help

 

Its probably a HPO leak, likely standpipes, dummy plugs and or failing STC fitting.

 

Should the dealer know to check for that or does it sound like they are throwing parts at it?

 

It sounds like they are throwing parts at it to me. Hot no starts/long cranks are almost without exception HPO related. Cold no starts are often FICM related. You really need a set of gauges that read live data like scan gauge II or one of the smartphone apps like Dashboss for IOS devices or torque pro for android, if you would have had a set of gauges they would have pointed you in the right direction ie: low FICM and or system voltage or low ICP during cranking would have pointed to a HPO leak.