Hard Starting, Slow Starting
This post is intended to be a possible solution for anyone who has had a hard starting or slow starting truck. I came home on leave from Iraq and about 3 days ago went to start the truck and noticed it wasn't turning over as aggressively as it should. It started just fine, just that it turned over very slowly.
I trouble-shooted using a volt meter and discovered that the recently installed altenator was putting out 13.8 volts at idle and that each battery held steady at about 12.5 volts when I turned the truck off.
I left to go back to Iraq today and my dad leaves to pick up my new boat in 3 days in Tulsa Oklahoma and I was worried about the truck breaking down. I convinced my dad to take it to the local mechanic who is very reputable and he did a simple load test and discovered the the right side (as you're sitting in the vehicle) battery was bad. It would take and hold a charge but would not retain a load.
$114 later for the new battery and she fires right up now. There are a myriad of different possibilities of what can be wrong when this occurs. Mine was as simple as a bad battery. Hope this helps any future searchers.