I am getting the dreaded p0087 low fuel rail pressure on my deleted 08 6.4. The strangest thing is that it only will occur if the ambient temperature outside is over about 65 degrees Fahrenheit. I live in Wyoming, and it almost always freezes here overnight, even in mid-summer. So I never ever get this code unless it is hot outside. Wondered if anyone else has been through this. Thanks very much

 

have you checked your filters (under carriage on drivers side and engine mounted)