Battery condition/charging system,
Dirty/loose battery connections,
Dirty/loose connections at the starter,
Worn out starter solenoid,
Worn out brushes in starter motor,
Worn out starter drive gear/flywheel assembly,
Faulty or out of adjustment neutral safety switch,
Faulty starter relay,
yes. a starter made for the 168 tooth flywheel would not engage a 153 tooth flywheel.
Could it be your starter won't work because... Ford didn't make a 1998 Thunderbird?
No, they're different.
It can if it is frozen to the point it will not work. Otherwise no.
i would check the cranking circuit,starter,starter relay,ignition switch,neutral safety switch.
No
yes!
Defective starter or weak battery. Can also be a loose connection at the starter.
a defective starter switch
No, they're different.
I would unhook the BATTERY and then Check the starter wires, Clean and tighten the wires on the starter and make sure there not touching anything that would make them short out / spark. That should fix your problem.
A very low (but not quite dead) battery will do that. It's the starter relay trying to work.