My 89 century runs fine with no missing As I drive down the interstate the engine just dies lik I'm not getting spark or fuel as I coast down the road when the engine just dies it starts right back up lik nothing I have replaced the ignition switch, icm, fuel pump, coil packs, map sensor, fuel pressure regulator, plugs, wires, air and fuel filters, computer, grounded the engine, keep in mind that the radio and all still are working when the engine stalls any idea what the problem could be please help