so today i got in my truck and i put my truck in gear, once i did this i noticed that my battery guage started to wiggle back and forth, it only does it in drive park or neutral, anyone know what the problem is? it starts fine...

 

Turn on your lights to create a load and check your voltage when the engine is running.
It should be between 13.8 and 14.8 volts.
If it is lower your alternator is not working properly and you are running off your battery.

 

voltage is at 14.5v

 

Sounds like a loose wire connection somewhere then or a gauge starting to go bad.