Wont start

ok I have 88 buick lesabre 3.8 it turns over but wont start and sometimes it will spit back out of the intake like a timing problem and a few times it has cranked up and ran fine for about 20 seconds or so then it cuts off clean. I put a new timing chain and gears but that wasnt it, I put a new crank position and cam sensor check fuel pressure it has 35 to 38 lbs when cranking its getting a spark to the plugs and they are new also, the car ran fine the day before when we drove it . anybody have any thoughts of what it could be

thanks

as a update I have found its not getting a injector pulse for some reason anybody know what that could be

Computer, perhaps. Possibly even the ICM.