had a similar problem...interference on my handheld ft60 in my jeep....turned out the car charger for my gps was cheap,,,found one
with an FCC approval and problem went away
I've got a '04 Limited I bought new . Its got the 4.7, put a Kolak 3.5 lift on it 10 years ago...it just turned 187,000 last week. just use it now to tow my flat fender now.