DevsHonda

I just installed a Skar EVL 12” package(came with everything) and I have everything hooked up. The remote wire is coming from radio fuse and I have the power cord and remote start running down one side of car, the RCA cables are in the back and connected to a RCA converter which is connected to both rear speakers, my problem comes in when I crank my car and with no audio coming through the OEM head unit it will still thump twice and then when I put it in drive, and drive off it will follow my engine noise until after around 2000 RPMs but when I put it in neutral or back in park I can turn it up as much as I want with the bass knob and it won’t make so much as a hiccup, and everything is fine. SOMEONE PLEASE HELP!! I’ve changed ground spots and sanded both but nothing. Any ideas??? Willing to try anything. My next step is to buy a ground isolator.