new car stero question

[89AlpineM3]

I just put in a new sony deck into my 91' 325IC, hooked up everything to the stock wiring. Radio works great but when I go to CD or hook up the USB the deck cuts in and out. Do I need to run the power wife stright to the batt. instead of using the stock wiring?

[EN318isPDX]

I just put in a new sony deck into my 91' 325IC, hooked up everything to the stock wiring. Radio works great but when I go to CD or hook up the USB the deck cuts in and out. Do I need to run the power wife stright to the batt. instead of using the stock wiring?

Stock wiring is fine, Might be a bad deck or possibly a short.