The AM band on my factory radio using the fender mount factory antenna sucks while the truck is running for all but the strongest stations. I suspect the ECU is causing all the interference, because when I shut the truck engine off, it is clear as a bell for every AM station, no matter how distant. FM is just fine.My FM radio in my 2011 Tundra works fine but the AM doesn't. The antenna is not visible and I can't seen anyway to make it work. Any hints?