Strong smell of fuel when idling - 2000 Ford Windstar

If you have a strong gasoline smell, get that car into a mechanic ASAP. Forget fooling around trying to discover the problem yourself. Gas explodes, right? You already have a strong smell. That means that somewhere down the fuel system line there is an active leak and that is dangerous. The fact you have to post here means you don't know anything about a car, so stop messing around with a potential lethal problem. I am an old alley mechanic from wayyyyy back and am speaking from experience.

you may have a fuel leak or your motor is running rich check the fuel tank and have your idle speed motor checked

timing problem??

check the fuel presure switch or (regulator)

possible fuel pressure regulator leaking high pressure fuel into attached vacuum hose

look at the fuel lines and injectors for signs of leakage.

You changed everything but the temperature sending unit/sensor. That's what is your problem as far as no proper cold start. When first started and cold, the sensor tells the computer to place the engine into cold start mode, engine starts and runs because it's at a bit higher idle and getting a bit more fuel. When warmed up, the sensor, if good, will tell the computer to place the engine into normal run mode now. Have the sensor tested first. If good, the engine is not going into a higher idle and is still getting the fuel but not using it fast enough because it's flooding. Hence the fuel smell. That's the fast idle solenoid on the EFI for this and the A/C high idle when it's running.

check all fuel lines, make sure there is no leaks

I would definatly recheck the regulator to make certain you do not have any leaks.
But to be clear, you are smelling gas and not exhaust?
Also, is you cowl seal in good shape, not missing or damaged in any way?
Let me know.
Regards,

You more than probably have a gas leak somewhere in the fuel system. If you can smell gasoline, it is leaking somewhere. The lines run along the frame to the engine. The leak might be hard to see or hidden (on top of the fuel tank).

The leak is robbing fuel pressure from the engine, causing it to idle rough, so is probably on the pressure side of the system.

(Most fuel systems, except for "returnless" systems with Pulse width modulated fuel pumps (not very common), have a pressure line and a return line to the tank.