Starting Troubleshoot - Heatsoak?

[franken]

Originally Posted by Jferrante

Bought a new high torque starter and installed it tonight - that thing spins it quick. Still getting hesitation after letting run a little but it seems the extra oompf in the new starter is what it needs to crank over. I think its a voltage problem as the starter seems to be spinning fine.
I did a quick check on battery voltage. Brand new battery 2 months ago and reading 12 -12.1 volts after running (should be higher)...13.5ish while on (seems right). I may need to charge the battery since the car does sit for days on end but it seems that isn't helping.
Thanks for the help.

You need to charge the battery disconnected on the - side from the truck for a few days, assuming a slow charge. That voltage reading is very low, and if the truck only sits for a few days is too low. After charging and running it, I'd disconnect the - battery cable each time after use and see if the trouble goes away.

If it does, you're looking at something discharging the battery when the vehicle isn't in use.