[shorod]

Sounds like you might have leaking injectors. After the car's been sitting overnight/for a long time, the leaking fuel evaporates or leaks past the piston rings. However, after you have been driving the car and try to start it up a short time later, there is still pressure in the fuel rail and the leaky injector(s) flood the cylinders with fuel. When you turn the key on, the fuel pump runs for about 3 seconds to prime the fuel system. This really floods the cylinders. When you hold the throttle wide open (WOT) the computer shuts off the injectors, allowing the car to start off of the excess fuel that's already in the cylinders.

You may want to start by putting a bottle of fuel injector cleaner into the gas tank and running it for 100 miles or so to see if that helps. It may just fix your problem.

You could also have a bad vacuum line or an out of range coolant temperature sensor. Well worth looking into before you invest in a bunch of injectors. Just right now my brain is thinking injector issue.

-Rod