The Crown Vics were exploding without being rear ended, and they were typically in motion. Big difference between a car that explodes on ya while you're driving it and one that explodes as the result of an accident.
Do you have a reference to this "problem"? Or are you making accusations with no evidence whatsoever?
The ONLY cases of Crown Vics "exploding" that I can find are rear-end collisions at VERY high speed.