Hey guys for some reason when I first turn the key on my truck I have really low voltage the needle drops to almost 8 and then I start it and it starts fine and volts go up after about 20-30 sec. Can you guys help me out I'm stumped

 

So it starts fine? Where do you live is it cold there? If so it's most likely just your grid heater cycling to heat the intake air when the engine is cold. It draws some serious power. You'll notice your headlights and soforth dim when the grid heater cycles, it's normal until the truck is warm. I wouldn't worry about it if it's starting fine

 

Ya truck starts fine lift pump runs a lil slow till volts go up and it isn't to cold here bout 35 degrees at coldest

 

The grid heater will circulate at 35degrees for sure