1990 buick riviera starting problem?

[Demarcus]

I have a 1990 buick riviera 3.8 v6 the car been having trouble starting. 2 days in the row the car will start but the third day it wont start for the whole day then the next day it will start. when this first happen I changed the coil pack and it started right up now its back to doing the same thing.The car cranks just wont start. I checked the fuel it have fuel pressure. Once the car is started it runs like a cham with know problems. the car only cut off on me 2 times since having this starting problem