Potential electrical issues

[jhoney]

I have replaced everything except the wire harness I'm at a loss. New fuel pump new ECU new plugs coils and injectors. New fuse block new cam and crank sensor also new iav valve. If I unplug the battery for a day or two when I plug it back in the truck will start but only stay running with throttle. It won't idle. Once it dies it won't start again without resetting the keep alive and unplugging the battery.
03 expy 200k.
Any help is appreciated.

 

[whtbronco]

Any codes?

To me it sounds like the Idle Air Control valve, though you say you replaced it I think if you called it IAV. If so try cleaning the throttle body.

 

[jhoney]

No codes and I cleaned the throttle body when I replaced the idle air control valve.

 

[whtbronco]

Couple thoughts. Is the port in the throttle body for the IAC valve intake plugged up maybe? Do you have a vacuum leak?

I haven't seen many of us suggesting to use a Motorcraft IAC, but my preference is Hitachi or Motorcraft. However, I would think even a poor quality brand new IAC would have helped if the original was faulty.

 

[Broncoholic]

Open EGR valve would cause stall at idle. Unplug the vacuum from the EGR valve, and plug the vacuum line, to see if it's getting constant vacuum. If that makes no difference, check to see if the EGR valve is stuck open. Stuck open would be unlikely, but worth checking.

Check for any other vacuum leaks with a smoke machine.

 

[whtbronco]

Wow, great response. I have even dealt with an EGR stuck open and did not think of it. A piece of carbon broke loose in my daughters old car and got caught in the EGR so the car died each time she stopped.