Ford products had a puny + battery cable that wouldn't turn the starter motor fast enough to start the car.. The problem caused a lot of starter solenoids to burn up.... I wouldn't buy a grounding kit but I do have heavy gauge cable that is going to be replacing the little cables since I will have a small Deka battery, more electronics and water/methanol squirting into a couple of 2 or 3 places to see if it will add more power.

 

I think i can easily say its probably the coil packs which is the most common fit problem by far.. I would do these before ripping your car apart