How hard or easy is it to check for a possible bad ground that may be causing interference in the audio system of my 2000 rx 300? Is there any link(s) to steps I can follow to check for this without having to pay a dealer? Thanks Matt

 

The two grounding points relevant to the radio reception ("bad ground") would be at the antenna mount (inside the rear fender) and at the radio mount to the metal chassis. If, on the other hand, you have a ground loop then that could be anywhere in the entire audio system.

What symptoms are you having (poor signal strength, ticking that increases with engine speed, whine that increases with engine speed)?

 

Well; I keep getting audio on the fm side that keeps getting "muffled" like it will go from a sort of normal tone pitch; to sounding like its muffled or crackling(almost like its playing in mono where the sound is muffled; it keeps going in and out from being normal to that). I was hoping that there was a easy way to determine whether its a bad ground or bad loop or possibly both. Is there a easy way to identify this?

 

The radio automatically switches to mono and reduces high frequencies when the signal strength is low. Yes, it sounds like a bad antenna signal. Could be the ground but more likely the center signal wire/connection. Note that the RX300 has a diversity antenna system and, in weak signal areas, switching between antennae can cause similar symptoms.