When cranking the engine cold it acts like it is flooded, or starved for gas. When it catches it "stumbles", which is sometimes cleared by feathering the gas pledel or holding it all the way down. As soon as it "clears" it runs fine and has power. Hot starts are fine, starts right up. Any ideas?

maybe a leaky injector? next time it has sat long enough that you feel it will fail, pull the plugs to see if one is wet.

 

Or, before a full start, cycle the key to ON, wait 6 seconds, then Off, then ON, wait 6 seconds - repeat. This should cause the pump to cycle on a few times, pressurizing the FI rails each time. THEN start the car. If normal, you're losing pressure in the rails. If the same or WORSE, probably an injector flooding a cylinder.

 

HOLDING the pedal on the floor is the clear flood procedure. If that helps the car start, probably a leaky injector or other flooding problem (maybe Engine Temp Sensor)