Flickering lights inside cab and out
 

Had this issue for a bit my lights had been flickering sometimes and now everytime i leave work at night they flicker bad almost to the point where they want to turn off awhen that happens my volts go from 14 to 10 or 0 then go back up all i have hooked up is a lightbar and amp but my amp and lightbar will work fine just inside lights and outside lights do this and my truck also has like a surge to it when it happens i really need some insight to as what it could ibe im hoping its just alternator checked all the wiring as well even driving on a bumpy road only does this while driving steady on highway

Are you sure it isn't the intake heater grid cutting on and off? What are the temperatures when this occurs? Do you get the symptoms the entire time you're driving, or just the first few minutes after startup?

The truck is completely warmed up i can druve on a rough road nothing smooth highway and they still flicker and dim till it seems like they are barely on and my voltage drops to 0 or 10 and its even gone up to 18 volts ive cleaned all my battery posts and cable ends and nothing seems to work i always let my truck warmup at least 10 minutes before i drive the truck is all stock just a light bar and amp and its also a 5spd 4x4 if that helps anything

So the entire truck has a problem except for the amp and light bar? Did you hook up the amp and light bar directly to the battery? If so look for a loose connection probably the body ground also check to see if you have a body ground connected and it's not just grounding through some metal component. In fact just use a single booster cable and clamp onto the grnd terminal of the battery and a good body ground point not engine ground, see if that changes anything.

There is a big 140A fuse in the PDC (fuse box under the hood) -

Sometimes the lugs of that fuse or the lug on the connector from the alternator to the box get lose or corroded.

Checked my amp for losse ground alls good driving on highway last night my lighta dimmed to the point where they were almost off and my volts dropped to 0 for avbout 2 minutes then came back up again with the lights and now im sitting in my truck setting up my fuel gauge and my dome light is flivkering as well havent had time to check for body grounds yet

Since the amp is working fine no need to check there.

You need to check chassis grounds ( especially the one behind the drivers side headlight where a lot of wires go) and the fuse and lugs in the PDC.
If the amp and lightbar are wired directly to the battery and they work OK you have an intermittant contact between the truck and the battery.