I recently purchased a 2003 2500 5.9LHO. It seems to idle up when I come to a stop sometimes and won't idle back down unless I really press the brake hard. Any thoughts? I'm new to these, my last truck was a 99 powerstroke.
Thanks,
Nick

 

what do mean when you come to a stop?? a traffic light? or when you put the truck in park? what is the temp outside when this happens?? these trucks have a high idle feature that will kick the rpm's up to 1000-if the outside temp is cold enough (when the truck is in park) to cancel this, you depress the brake pedal.

 

My 03 will idles up when it cold out and I don't have my foot on the brake. All I have to do is tap the brake or the fuel and it will idle down.

 

my 04.5 will do this also go up to around 900 then go back down to 750 when i am at a stop

 

The best way to describe when it does it is when I drive up my driveway (uphill) in first gear with some gas pedal used. When I push in the clutch and step on the brake at the top it stays at around 1000 rpm. It won't idle down until I really mash the brake hard. It does it to in the morning when I back into my spot at work. Both times are after a 20+ minute drive on the highway so I don't think it's because it's cold outside. Thanks,
Nick

 

Do you have stock exhaust, and a big programmer, my buddies 03, auto did the same thing when he had a bully dog and stock exhaust but we straight piped it and it stopped.

 

Nope, 4" from where the muffler was back, no chip at all and it's a stick.
Nick

 

Same issue was discussed at TDR and it was fixed by replacing a defective connector block that goes into ECM as the pins were not sized properly.The problem was also tied to erratic cooling fan operations and door lock issue.