I’m stumped. My 2003 f150 with 5.4 will not start after you shut it off. If you let it completely cool down It will sometimes start right up. Other times it just turns over. I replaced timing chains on it a few months ago. It’s been running good till now. When it does start it runs great. I’ve replaced fuel pump, fuel filter, fuel pressure regulator, crank position sensor, cam position sensor, cylinder head temp sensor, cleaned maf, throttle body, iac. I have good fuel pressure at all times. Only code I’m getting says it’s running lean. Any help would be greatly appreciated. Could it be pcm?

 

Exactly what code are you getting ?

 

You have changed a lot of parts and just because a part is new does not mean it's good. What is the actual fuel pressure when it won't start?