Can't figure out from the original posts if the interference only happened with the engine off. This is not so mysterious, but don't look for a standard solution to any RFI problem. If the radio itself is causing interference, it might be from the FM section's local oscillator leaking backwards out the antenna, or out the power plug, or out the speaker connector. Why else would a radio be radiating 140 MHz?
It can take multiple routes. Pulling connectors one at a time can help you to diagnose. Don't be amazed that the interference changes or goes away under certain conditions. Every time you alter the car's electrical system by starting the engine, stepping on the brakes, turning the headlights on, etc, you are switching in a different part of the overall electrical harness, which might make the interference worse or better. I'd stick with the radio on this one until you prove otherwise. I doubt if the cars EMU is operating anywhere near 140 MHz.
FF