Hard starting in the morning easy to start but hard starting when the engine is warm

With what you've provided, it could be any number of issues. Just guessing from the year and make it'll need a good tune up if you've never done one before.

Start simple and and begin with replacing the plugs and wires...sometimes this can be the difference between night and day! And although some may say otherwise, depending on where you get your fuel you may want to change the fuel filter if the problem persists.

The valve body is worn to the extent that when engine heat warms up the transmission , pressure leaks around the shuttle valves in the body and then the trouble starts.

When you park your truk at night,the engine is warm/hot.Now its start to cool down.In doing so,condensation collects under the hood and around the cooling off engine.The condensation freezes,making everything wet,including the wires.Tht's why its hard to start in the morning.
Trick is: when engine is parked and off,place a heavy blanket over the engine,close the hood.The blanket will absorb any condensation.Just remember to remove the blanket in the morning before you start the engine.

May just be a bad temperature sending unit. Once warmed up, it's supposed to go off cold start, which puts more fuel to the engine. If sending unit is not telling the computer the engine is warm, it will still be putting more fuel into the engine and flooding it, making it hard to start. Check/replace said sending unit and you're good.

Is the base fuel pressure the same hot when it is cold, and so is the spark weak when the engine is hot ?

The engine coolant temperature sensor could be stuck in the cold mode. This would activate the cold start injector even with the engine warm--and flood the engine with too much fuel, making for long crank times. The engine coolant temperature sensor (ECT) is usually located close to the thermostat housing. It has two wires coming from it. The coolant temperature sender for the dash gauge is not the same. It only has one wire and grounds through the engine block. It is easy to get them confused.

The cold start valve is not operating correctly. Either the engine coolant temperature sensor is bad or the cold start valve itself is bad. You can check the engine coolant temperature sensor by going to radio shack or any electronic store and purchase a 15k ohm or higher resistor. Disconnect the engine coolant temperature sensor (ECTS) harness. Bridge the 2 female spade connections in the harness with the resistor. Start the engine. If the engine starts you need to replace the ECTS. If the engine is still hard to start, you need to remove the cold start valve, (wear safety goggles, and whatever you do don't smoke) place the cold start valve in a glass and have someone crank the engine. You should see gas coming out from the cold start valve. If not take a ohm meter and measure the terminal at the cold start valve after disconnecting the wire harness. The meter should read 25 ohms. If it doesn't replace the cold start valve.

cant start deisel 3.0 lilter sounds like there is no fuel getting to the engine

It may be due to a failed/faulty fuel pressure regulator. I had this problem: easy start when cold, hard starting when warm/hot, and rotten egg smell from exhaust when warm/hot. My mechanic diagnosed a failed/faulty fuel pressure regulator, replaced it, and now the problems (warm hard start, smell) are gone. I have a '92 GT with L4 engine.

Coolant temperature sensor sounds like it went bad. It is reading that the engine is warm all the time, so the computer is not commanding additional fuel for startup. Easy and cheap fix.