1989 Buick Century • 144,916 miles

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 the engine start right Back up without me turning the key 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, I also drove the car with a computer hooked to it and no code came up not even when the car died. Keep in mind that the radio and all still are working and do not shut off unless I turn it off when the engine stalls any idea what the problem could be please help
October 28, 2012.

Are you losing the rpm signal? Comes from crank sensor. I didn't look at your wiring, not sure of engine litre size?

Oct 28, 2012.