When going 5-50mph the tac falls to zero and car is now dead but volt meter oil pressure gage stays up. Take foot of gas just coast and tac will bounce back up and car is now back with power. That will happen approximately seven times then the car will be fine for the rest of the day. Only happens when car has sat ten hrs or more. New parts in car. Cap roter wires ignition mod battery- starter and fuel injectors. 5.7 liter v-8. Help. Ty.

 

Have you scanned it for codes? There are codes that shut down the engine, but don't turn on the SES light.

Have you checked the fuel pressure with the engine under load?