Intermittent starting issue with good battery

[charles ovalles]

Hi everyone,  I have a 2015 Tahoe LT 5.3 with 72k. My truck started having a very long almost like a dead battery start but always starts. I have a push start button. My main battery is less than a year old and reads 14.5v and I have a second battery for media that is also reading 14v. I also have a Big 3 mod for media. All media mods where done over 2 yrs ago. My truck has always started fine till a few weeks back I noticed it barely turning over as if a dead battery. It will turn over very sluggish at random starts and sometimes starts like a champ. I did notice all dash lights go out on start and than boom everything works fine. Almost as if a relay or solenoid sticking or something. Oh this happens at all times of day, hot after a long drive or even on cold starts. I live in south florida. This only happens sometimes so I am hoping I don't get stuck somewhere soon.  I'm guessing my starter might be going but before I cash out on the parts I want some insight from the pros. I take myself to be very mechanically inclined so please I am all ears! Thank you again for taking time to help. 

[diyer2]

Starter IMO