AM radio interference from car

This is weird topic, but I don't know where else to go.

I like a certain AM radio station, but the signal is weak.
In my old truck, the reception is great. In my wife's suburban
it's great. In my Mustang, it sucks.

Some of the symptoms are, when the engine revs, or when
anything electrical is happening, I get more noise. Turn signals,
I can hear it through the radio, but only when I'm trying to
bring in this particular station (ESPN Radio, from about 30
miles away...).

I had the original Mach 460 head unit in, and it was bad. I
replaced the head unit with a Pioneer unit, and it was just as
bad.

It seems to be an electrical thing. A poor ground? For spark
plugs, I use the standard Autolite... forget the number but I
think they are the resistor plugs.

Any ideas?

Thanks for the ideas... I had no idea about the hood blanket.

Speaking of the antenna, I bought a cheap aftermarket antenna..... little piece of crap.... now that I install it, if I take it out it leaves a bolt stuck down in the antenna mount, so now I can't take it out and put the original back in, blah, blah...

The antenna itself is not the problem, as the radio was bad when the original antenna was in there. But, I'm wondering how to safely take the antenna mount out and inspect that? I used to do this with a pre-94 car, but I don't see how to do it with this one (98).