I have a 2006 E-150 Van 5.4L V8 with a problem.

I know this is not the same as a F-150 but is similar and this forum has a better reputation than most.

It has a rough idle/surge problem. Only at idle this occurs, in park or in drive at a stop or at low RPM's when moving. It does not occur when it is first cold started. But does when started if the engine is at all warm. Air temperature does not matter it has been between 50F-0F and still does it. BUT, it started when it first got really cold (below 15F)

It has trouble staying at idle dropping below 500 RPM and occasionally surging to 900-1100 RPM.

It does die if parked or standing still 25% of the time.

Driving/accelerating is not a problem. It does not appear to be a fuel issue, I did change the fuel filter before this started, but a month must have gone by before this problem started. I ran a tank of treated gas through it, no change.

I drive this van 1000-2000 miles a month, so it gets wear and tare

My First thought was IAC valve but its fine when cold. I know it could be the EGR or Vacuum Line too.

Any Suggestions

 

There should be a sensor on your intake that monitors air flow and tells your ECM what to do with it. I good way to test this is, just un plug it and see if the idle levels out. When you unplug it your ECM will automatically refer to other parameters to monitor air flow. I had to replace mine and it was doing the same thing your talking about. If it levels out, you can clean it with mass airflow sensor cleaner, do not use anything else, it will kill it. Hope this helps