Any help here would be appreciated have a99 with a 5.4that won't idle 90% of the time.I broke down and went and bought what I think is a pretty good code scanner. It came up with 2 codes and definitions.
P0401 EGR flow insufficient
P1507 Manufacturer control speed control, idle control, and aux. inputs
From what I read it seems more likely to be the IAV valve? Is it possible to check this valve or for 40$ just replace and hope.
Any help is appreciated. I always refused to work on this thing until today. I'm not mechanically dumb just refused to buy metric tools. So I stuck to my old pickups and tractor trailer.

 

Welcome to FTE hotrod99. It sure sounds like your idle air control valve and almost always becomes a problem with vehicles of this age.

I personnaly am not aware of any specific ways to test, but perhaps someone else can drop on in and share their experience.