good cold start bad warm start

[6030pullr]

03 lb7 90k
new f.f.

starts fine cold{sitting overnight}
have to crank it forever after it has warmed up to get it to start.
always runs good when running.
is there a relief valve that gets weak after warming up or could it be the injectors????
had it to the dealer 6mo ago before warr went off "inj balance ok and rail pressure checks ok" even though i could tell it was cranking a little bit longer, but it wasn't noticable to the average guy.

and here i sit no longer under warr because it's after the 1st of the year and can't be put under that ticket !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!

[More Power]

Welcome to the board!

Change the fuel filter as a first step.

Fuel rail pressures could be low. High fuel return rates or a worn high pressure CP3 could be the cause of hard hot starts. A Tech II Scan tool can be used to check rail pressures...

Jim