01 tahoe ls stereo noise

[60ratrod]

so i have a noise coming from my stereo, mostly the front passenger door speakers, that fluctuates with my rpms. i turn the stereo off and the noise goes away. sometimes if i shut off the stereo before i shut my tahoe off and turn it on after i start my tahoe the noise will go away for a while. the stereo is a pioneer aftermarket unit that you can get from walmart for $100. and my tahoe is equipped with a factory sub and amp. i ended up cutting the factory harness connector off and installed the stereo with a print off of the stereo wiring diagrams. is it possible the speed wire for auto volume leveling with the factory radio is causing interferance? or could i be getting feedback from somewhere else?? could the amp be going bad??