I have a 1996 ford F150 300 6 cylinder that will occasionally barely run after starting. This problem doesn't happen all the time and only happens after I've been driving around for a while (when engine is at operating temp.) After a few minutes of wondering if it will die or not it smooths out. I have discovered that it I depress the accelerator immediately after it starts it will smooth out almost immediately. It acts like it's flooded. I've replaced 2 oxygen sensors and installed a new Air Idle Control Valve. This problem has been going on for almost 2 years but it seems to be happening more and more frequently. Any help would be greatly appreciated!

 

Try replacing the fuel filter and see if it helps.