1998 el ford falcon cuts out after 5 min turn key to off position to start again dissy ,coil ,bcm & computer have been replaced

It probably has fuel injection. There are sensors that tell the fuel injection how much fuel to put into the engine. The auto supplies sell a diagnostic tool that you plug into a socket on the car, usually under the dash. Plug it in and it will flash a dash light in the dash to tell you what is wrong (like morse code). I've used it on my 93 chevy truck and it flashes number 1 pause, then 2, both three times, that's a 12 means starting diagnostic, then flashes number of what part or parts are functioning wrong, made for many makes of car. Recently mine had similar problem, coolant sensor was telling engine computer it was hotter than car actually was, had to hold throttle to floor to start, it was code 15. The instructions tell you what that means. That might help you.