Just did a fuel pressure test on my truck and while idling the needle on the guage bounced extremely fast between 60-70 psi. Is this just a symptom of a crappy guage or an actual issue with the truck?

 

When the injectors open and close they create pressure waves, these waves can be an issue when running fuel pressure above 45psi, because they can propagate, so there is a Pulse Damper at the end of the fuel rail which absorbs the pressure waves so they don't get worse.

It is normal to see fuel pressure pulses with running engine, the 10psi difference won't effect much