No, it's the HU. Pioneer's have weak internal grounding circuits. Once you pick up a loop the resulting ground modulation will weaken the internal grounding circuits inside the HU. Sometimes it can be overcome by finding an extremely low resistance grounding point (in your case the battery negative is .30 ohms so it works). Don't be surprised if it comes back in a few weeks or months. If it does move the HU back by the amps and connect it with some short RCA jumpers. If the noise is still there you will know that the HU needs to be sent to Pioneer and have the circuits replaced or upgraded. It is a problem they are very well aware of but won't readily admit to .
Originally posted by Kyle1058:
fixed it by running a new 4 gauge ground cable, however it wasnt enough to keep up with my amp and ill need to get 0 gauge soon.
Interesting. i touch the ground to any other frame location and it picks up the noise, i run it straight from the battery to nothing else and its clean as day. Must be my car.