One more Taurus problem. I get a lot of engine noise (electrical noise)when I'm listening to AM stations. The sounds pops in perfect tune with the cylinders. I've placed a grounded filter on the power supply. This fixed a problem with an old mustang I have, but did not have any effect on the taurus. Where should I sink money into next?

Stop into a good car audio shop and ask them about filters. There are very good filters out now days that will fix most problems.
Have you replaced your ignition wires lately? It may be a case where the old wires are unshielded.

check your plug wires be sure to use resistor plugs (chances are you are) put dieelectric grease (available at autozone) on both ends of each plug and coil wire