i have a 2003 6.0 that whin its started runs rough for a few seconds and then idles up to 1000 rpm any ideas of what causes this.

a little history on the truck, i had a ficm go out a few months ago and 600 miles later i lost an injector and thats whin my high idle problem showed up. found #3 injuctor nozzle was cracked and had fuel in the oil. changed injector and oil. today i changed the icp and still have the same problem. and it will not idle down at all

 

They have a factory high idle to warm them up faster but it shouldn't do it when it's warm

 

it dose this warm or cold was thinking ipr might be the problem but not sure yet

 

The high idle is probably just a reaction to something else wrong. The truck is probably just trying to keep itself running.

Why was the ICP replaced? Was this diagnosed as bad, or was it put on just hoping it would fix something?

Try unplugging the ICP sensor and starting it and see what happens.

How old are your batteries? They should be load tested, especially since you just had a FICM failure and an injector crap out. Bad batteries could kill a FICM.

 

batteries were replaced along with the ficm, i connected an otc genisys scanner to my truck and it picked up a few codes for icp signal and voltage, found oil leaking out of icp while replacing it and oil soaked harness, new icp harness is on order. also had a code for high injection pressure.

 

Ah! The ICP harness and ICP should be replaced at the same time on the 03/early 04's. Very common issue. Make sure to cut the harness back to where there is NO oil contamination. I'd be surprised if this doesn't fix your issue.

 

Was the high idle issue ever figured out my 2006 f250 has the same issue with no faults.