2004 Ford F150 Fx4 Weird Idle

[fastford04]

You could be driving down the road perfect runs good but come to a stop sign or a red light you hafto put it up in neutral to keep it runnin like it doesnt want to idle its really worse at night with the headlights on like it doesnt want to idle at all in drive, ive tried doin what my owners manual says to do about resettin the idle and fuel trim but it hasnt helped a bit im kinda stumped....also when you have it in park or in gear with the headlights and fog lights on they are really dim an you can rev the motor up a bit an they brighten up...

As far as codes when it dies it hasnt set any....im so confused

Could the battery possible be bad?

I know last winter when it dropped down real cold if it say for 2-3 days while i was workin it would hafto be jumped off..

The battery's never been changed its the factory Ford battery from 2004...

 

[rusty ol ranger]

It could be the battery, or the Alternator. I wouldnt know why it would make it idle weird though....unless the computer isnt getting the juice it needs?

I would change those first.

It could also possibly be the IAC, a common problem on the 4.6L/5.4L.

later,
Dustin