Hot blooded?.......My son-in-law acquired a 2005 F-150 recently with about all the options including the security key system with the 4.6 v8.
Everything worked fine until the North Carolina weather cooled off a bit.
When the temperature hits 50 degrees or below, the engine will not
fire. Dash lights and other stuff comes on with the key, but no start. Above 50 degrees it cranks fine.......What is?????

 

First off more information would be very usefull. A 2005 shouldn't have a 4.6 V8 it should have a 5.4V8. First thing I would think to try is to hold the throttle down a little and see if it will fire up. If so then look to see if the idle air control valve. Mileage could be a factor also. if it is the 5,4 V8 then it should have the finewire sparkplugs. Alot of people gont want to pay the price to change them out because they break off when you remove them. Double check the information and let us know.