Car shuts off while on interstate

So i was traveling home for the holidays a few days ago and my 06 spec b lost power for a half second and then regained it. (rpms dropped from 3300ish to 2000). It also flashed startup lights and turned my nav screen off and cruise control.

 

IT happened 2 or 3 times after but this time it didnt lose power it just flashed the nav screen and flickered my lights but it did this when i used my turn signal and my moon roof.

 

Any ideas on what is wrong? Battery is less than 4 months old only mods are cobb intake and fully updated accessport v2 map and hids that have been fine for 2 years.

Check all of the main power connections, especially under the hood. Make sure the battery and alternator connections are tight and that there's no corrosion. Same with the ground points. I haven't been under the hood of my LGT much yet to know...but I assume there's a fuse box or two. Check the main power connections on those to be clean and tight. Just a little corrosion or slightly loose connection can make a huge difference.

 

I had a Cutlass that did this, turned out to be a loose connection on the main under-hood fuse box.

 

I've also had a Monte Carlo do this. Turned out that the PCM went bad and would quit working when it got hot under the hood. Everything would shut down for a split second, all the start-up lights would come on like you just started the car, and then you'd keep driving until it happened again. Over time it go worse to the point that the car wasn't driveable. It took forever to track down the problem to the PCM. The PCM in that car had an aftermarket tune like the ECU in yours which might have caused the failure.

Loose battery connection?

As mentioned checked the battery terminals ^^ but it could also be a bad alternator. No battery light?

terminals are tight and clean and battery light is not on. tested battery while running and it tested at 14.6

A bad alternator shouldn't cause those symptoms I wouldn't think. And since you've got 14.6 V, your alternator seems fine. If the dash is doing the start-up routine, the ECU is losing power or shutting down for a split second, based on my experience. Check the wiring harness to it as well.

main relay i would think ..