hi JMM - have you changed out your spark plug wires???
the reason you are getting the static is because you picking up RF
energy that is being introduced into the antenna lead. since it is not
probably being picked from the portion that is sticking out of the car,
you will have to look at the cable run that the lead is in. now,
chances are, you pick up the unusual stuff when it goes by a area of
higher current applications, such as power windows. you might hear a
compliant about every time they roll down the passenger's side window,
they hear it in the radio, but no other windows will cause it.
the key to where to look is your 4 mph symptom. as the rpm's pick up,
if it is the spark plugs wires, you will hear a repeating sound, but if
you alternator suppression circuit is shot, you will hear a buzzing
sound, since that is the type of static it produces.
as a quick check. pop off the fan belt, and start the car and rev it
up. if you don't have any static on your radio, you just cut your
problem solving time a lot.
best of luck.
knowledge is power - growing old is mandatory - growing wise is optional