So FYI all.
I finally got the Ranger back and yes....it was the AMP that was the issue. They call the AMP a DSP. Either way its fixed now. Hope this helps anyone having this same type of issue in the future.
Anyone get any useful info back on this issue? I've recently took my Ranger in for this very problem. I got the dealer to order amp proactively however they didn't install because there were no audio problem codes popped up. I found that strange but they said there would have to be a "Technical...