After market radio (noise when driving)
 

I purchased my RX8 last month, it had a cheap after market radio in it which would always make an annoying hissing noise when I'd accelerate so a few days ago I got a Pioneer installed at Best Buy.

Two problems, the first was the audio which would go out whenever I'd hit the clutch then put it in first gear then only come back on after I turned the engine off. The tech took out a power antenna wire wich solved that problem for some reason but when I accelerate in gears 1-4 the audio sounds garbled and distorted, really choppy almost like bad static but worse but after I get it into 5th gear on the highway it sounds normal. The last radio had the hissing noise but no distortion this radio is really poor sound quality when driving.

I'm gonna bring it back to Best Buy but I wanted to run it by you guys first so if anyone knows the possible cause and cure please let me know

Thanks

Does it sound like a ground loop issue?