I have an 03 ford f-150 4.6liter. I'm having problems with it right now as far as when the truck is idoling. It starts fine but if you don't accelerate after start up it will die when it drops to around 500 rpm or idol. I changed out the fuel filter and the plugs but there is no check engine light on and I'm kind of at a loss because i've never seen a fuel pump act this way although that is what some are suggesting. Need some help if you don't mind.
Thanks

 

Clean the IAC really good with carb cleaner. Reset the computer by disconnecting the battery for 5 minutes. See if that fixes it....very common problem on these trucks is dirty/bad IAC